CN112927916A

CN112927916A - Inductance element and manufacturing method thereof

Info

Publication number: CN112927916A
Application number: CN202110098433.5A
Authority: CN
Inventors: 柯昕
Original assignee: Zhejiang Santi Technology Co ltd
Current assignee: Zhejiang Santi Technology Co ltd
Priority date: 2021-01-25
Filing date: 2021-01-25
Publication date: 2021-06-08

Abstract

The invention provides an inductance element and a manufacturing method thereof, wherein the inductance element comprises a lead and a magnet, two ends of the lead are exposed out of the magnet, the magnet comprises iron-based magnetic powder particles, and the iron-based magnetic powder particles are coated with a composite insulating layer of ferrite and silicon dioxide and can bear higher temperature, so that the comprehensive performance of the inductance element is improved.

Description

Inductance element and manufacturing method thereof

Technical Field

The invention relates to the field of electric element manufacturing, in particular to a manufacturing method of an inductance element.

Background

With the development of the market and the progress of electronic technology, the inductance component is continuously developed to the target of large current, high frequency, small size and low power consumption. The frequency and the magnitude of ripple current flowing through the inductor are increased continuously, which leads to the increase of the heat generation of the inductor, and puts higher requirements on the magnet loss and the conductor loss of the inductor, and also requires that the heat generated by the coil and the magnetic core in the inductor is dissipated quickly and effectively, because the heat generation is more, and the continuous accumulation can increase the operating temperature of the inductor and reduce the efficiency of the inductor, and even can lead to the burnout of the whole element. Especially, the development of 5G communication and automotive electronics has more strict specifications and requirements for the size and characteristics of the inductance element.

Some inductive elements are mounted on the automobile, and the automobile body always has vibration with different frequencies and amplitudes during the driving process of the automobile, and particularly shakes violently when passing through a section with uneven pits. In the conventional chip inductor, only the adhesive is used for fixing the inductor magnet and the pins, and when the inductor is shaken or vibrated, the adhesive used for fixing the inductor magnet and the pins may be loosened, so that the inductor magnet or the pins are peeled off, and the inductor element fails.

The current large-current inductor with equivalent number of turns less than or equal to 1 is mainly assembled by an assembly process, the assembly between a magnet and a conductor needs to be matched with tolerance, glue adhered between magnetic cores has certain thickness, gaps do not promote DCR and saturation current of the inductor, the waste of inductor space is caused, the inductor with the same performance and smaller volume cannot be manufactured, or the inductor with the same volume and better performance has the reliability risk of loosening of the adhesive.

Patent CN107749340A discloses a high-reliability large-current die-pressing inductor and a manufacturing method thereof, wherein the middle part of a lead is arranged in a magnet and integrated with the magnet, and the gap between the magnet and a conductor is reduced, but in the method, magnetic powder is coated by using an organic adhesive only, the magnetic permeability of the magnet is only 40-80, the organic adhesive and a lubricant are decomposed and volatilized after heat treatment at 500 ℃ with 100 plus materials, holes are left in the conductor, and the insulation and the adhesion of the coating layer are reduced, so that the inductor has low inductance, high power consumption, and poor high temperature resistance and direct-current voltage resistance.

Disclosure of Invention

One aspect of the present invention relates to a method of manufacturing an inductance component, comprising the steps of:

s1c, carrying out surface film forming reaction on iron-based magnetic powder, generating a composite insulating layer of ferrite and silicon dioxide on the surface, and mixing the iron-based magnetic powder subjected to the surface film forming reaction with a binder and a lubricant according to a certain proportion to obtain magnetic powder for pressing;

s2c, placing a lead in the die;

s3c, filling the magnetic powder for pressing into a mold, exposing two ends of the wire outside the magnetic powder for pressing, pressing to enable the wire and the magnetic powder for pressing to be integrated, and demolding to obtain an integrated inductance pressed compact;

and S4c, performing high-temperature heat treatment on the inductance pressed compact to obtain the inductance element.

When the iron-based magnetic powder is extruded by large pressing pressure, plastic deformation can occur to generate dislocation and slippage of a grain boundary, so that the internal stress of a magnet is increased to influence the rotation of a magnetic domain, the magnetic performance is deteriorated, and the pressing stress is removed by high-temperature annealing heat treatment to obtain better magnetic performance.

According to the invention, the iron-based magnetic powder is subjected to surface film forming reaction, and the composite insulating layer of ferrite and silicon dioxide is generated on the surface, so that compared with the traditional method that an organic adhesive is used, such as silicone resin, when the iron-based magnetic powder is coated, the iron-based magnetic powder can bear higher temperature, and the magnet can select higher annealing temperature, thus the inductance, power consumption, high temperature resistance and direct-current voltage resistance of the inductance element are improved, the annealing temperature can be selected according to different performance requirements of the inductance, and the inductance element can be stably in service under a higher temperature working state.

Further, in the step S1c, the surface film forming reaction is performed by adding the iron-based magnetic powder to an aqueous solution of at least one of phosphoric acid, phosphate, chromic acid, chromate, silicate, sulfate, and borate and a silane coupling agent.

The composite insulating layer of ferrous salt and silicon dioxide is generated on the surface by reaction, and can bear the high temperature of 960 ℃ at most.

Further, the method also comprises the following steps:

s2a, conducting surface insulation treatment on the conducting wire in the step S2c by using nano oxides, forming a nano composite insulating layer on the surface of the conducting wire, and uniformly distributing the nano oxides on the nano composite insulating layer.

The conventional wire is insulated by wrapping the surface of a copper wire with resin paint, the resin paint can be only used at a low temperature of below 200 ℃, carbonization is carried out after high-temperature annealing, the insulation effect is lost, volatile matters during carbonization penetrate into magnetic powder particles for pressing, the insulation property among the powder is reduced, and the inductance power consumption is increased and the inductance is reduced. According to the invention, the nano oxide is used for surface insulation treatment, the nano composite insulating layer is formed on the surface of the lead, the nano oxide can bear higher annealing temperature without changing the characteristics, and when the nano composite insulating layer is thin, the direct current voltage resistance of the inductor can be obviously improved under the condition of slightly reducing the inductance.

Further, the conducting wire in the step S2a is a copper wire, and the surface insulation treatment is to immerse the copper wire in a silane coupling agent and diluent in a weight ratio of 1: 2-10 min, preferably 1: 4-6 mixed liquid, preferably 2-5 min, taking out, draining residual liquid on the surface, and then putting into an aqueous suspension of nano silicon dioxide, nano aluminum oxide and sodium silicate, preferably in a weight ratio of nano silicon dioxide: nano aluminum oxide: sodium silicate = 2-5: 2-5: soaking the wire in 90-96 aqueous suspension for 1-3min, taking out, putting into an oven at 60-100 ℃, preferably 70-80 ℃, and drying to form a layer of nano composite insulating layer on the surface of the wire, wherein nano oxides are uniformly distributed on the nano composite insulating layer.

The nano silicon dioxide is adsorbed on the surface of the copper wire, and the nano aluminum oxide is added to fully disperse the nano silicon dioxide in the suspension liquid, so that the nano silicon dioxide is more uniformly adsorbed on the surface of the copper wire, a nano composite insulating layer is formed on the surface of the wire, the formed nano oxide can bear the annealing temperature of 700 ℃ without changing the characteristics, and when the thickness of the nano composite insulating layer is thin, the direct-current voltage resistance of the inductor can be remarkably improved under the condition of slightly reducing the inductance.

Further, the high-temperature heat treatment of the step S4c includes two stages of preheating and annealing, the preheating temperature is 100-300 ℃, the holding time is not less than 30min, the annealing temperature is 500-960 ℃, preferably 650-800 ℃, more preferably 700-750 ℃, the holding time is 10-40 min, preferably 20-30 min, at least one of nitrogen, hydrogen and argon is used as a protective atmosphere, or the vacuum pumping is less than 0.1Pa, preferably less than 0.02 Pa.

The iron-based magnetic powder can generate plastic deformation to generate dislocation and slippage of a grain boundary when being extruded by large pressing pressure, so that the internal stress of a magnet is increased to influence the rotation of a magnetic domain, the magnetic performance is deteriorated, the pressing stress can be eliminated through annealing heat treatment, the higher the annealing temperature is, the better the stress removing effect is, when the annealing temperature exceeds the Curie temperature of the magnetic powder, the pressing stress can be completely eliminated in a close way, and the best magnetic performance can be obtained. When an organic adhesive such as silicone resin is used for coating iron-based magnetic powder, the silicone resin can be converted into a glass state under a low-temperature baking condition to realize the insulation coating of the magnetic powder, but the decomposition temperature point of hydrocarbon oxygen groups of the silicone resin is far lower than the Curie temperature of most iron-based magnetic powder. The best performance of the magnetic powder cannot be achieved by using annealing conditions far below the curie temperature, and the magnetic powder is degraded by breaking the glassy coating layer due to gas escaping from the magnet when annealed at a high temperature of more than 500 ℃.

According to the invention, the iron-based magnetic powder is subjected to surface film forming reaction, a composite insulating layer of ferrite and silicon dioxide is generated on the surface, the maximum temperature of 960 ℃ can be borne, and the Curie temperature of most of the iron-based magnetic powder can be covered, so that the annealing temperature of 500-960 ℃, preferably 650-800 ℃, and further preferably 700-750 ℃ is selected, so that the performance of the inductance element is improved.

Further, the method also comprises the following steps:

s5c, immersing the inductance element subjected to high-temperature heat treatment into resin for 0.2-3 h, preferably 0.5-1 h, taking out the inductance element, cleaning the resin remained on the surface by using an organic solvent, placing the inductance element into an oven under a protective gas atmosphere, baking and curing for 1-3 h, and preferably performing the step under the condition of vacuumizing less than 1 Pa.

The binder and the release agent in the magnetic powder for pressing contain hydrocarbon-oxygen groups, and can be decomposed into gas to leave the interior of the inductor in the high-temperature annealing process, and a large number of fine pores can be left in the interior of the magnet due to the decomposition of the binder and the release agent. The inductor is immersed in the resin, and the resin is absorbed into the magnet under the action of capillary force to fill the pores in the magnet. The resin in the pores is solidified through high-temperature baking, the solidified resin bonds the iron-based magnetic powder together, the mechanical strength of the inductor can be greatly improved, the inductance cannot be reduced or the power consumption of the inductor cannot be increased, different types of resin can obtain different bending strength and tensile strength combinations, and the types of the resin can be selected according to the use scene of the inductor.

Further, the method also comprises the following steps:

s2b, pressing the magnetic powder for pressing in the step S1c into a prefabricated bottom blank, wherein the prefabricated bottom blank is provided with a limiting wire guide groove, and the copper wire processed in the step S2a is placed in the limiting wire guide groove according to the designed direction;

and in the step S2c, the assembled prefabricated bottom blank and the copper wire are placed at the bottom of the mold.

The limiting wire groove supports and positions the wire, and the wire is prevented from being deviated due to uneven stress in the pressing process.

Further, the method also comprises the following steps:

s6c, covering and protecting the lead wires exposed out of the magnet part by using a high-temperature adhesive tape, or protecting the exposed lead wires by using an immersion agent;

s7c, preheating the inductor to 130-160 ℃, spraying at least one of a layer of gray alkyd paint, epoxy paint, phenolic varnish and epoxy polyester phenolic varnish with the thickness of 0.02-0.1mm on the surface of the inductor, and baking and curing at 130-160 ℃ after spraying.

The iron-based magnetic powder has large specific surface area and high surface activity, and a metal interface is easy to generate chemical or electrochemical multiphase reaction, so that metal is converted into an oxidation state and generates a corrosion reaction to influence the appearance of a product. The invention seals the contact of the metal base material with air and harmful substances by adhering a paint film on the surface of the metal, thereby achieving the purpose of rust prevention. Meanwhile, the paint layer can improve the insulation resistance between the copper wire and the magnetic powder, so that the anti-rust purpose is achieved, and the direct-current voltage resistance can be improved.

Further, the method also comprises the following steps:

s8c, bending two ends of a copper wire exposed out of the magnet, enabling the two ends of the copper wire to be attached to the surface of the magnet to form an electrode pin, removing the nano composite insulating layer on the surface of the copper wire by mechanically polishing or etching with laser on the surface of the electrode pin, and then carrying out tin immersion or tin plating treatment on the pin.

Further, the method also comprises the following steps:

s8d, punching and bending the tinned copper sheet, prefabricating electrode pins, assembling two ends of the copper wire exposed out of the magnet with the electrode pins, and welding two ends of the copper wire with the electrode pins.

When the lead is thicker, the electrode pin is manufactured in advance because the magnet is easily damaged in the turnover process, then the electrode pin and the lead of the inductor exposing the magnet are assembled, the electrode pin and the lead are positioned through the fit clearance of the electrode pin and the lead of the inductor exposing the magnet, and the electrode pin and the lead are mechanically and electrically connected through welding technologies such as brazing or laser welding.

Furthermore, a plurality of limiting wire guiding grooves are arranged on the prefabricated bottom in the step S2b, and the corresponding number of copper wires processed in the step S2a are placed in the limiting wire guiding grooves according to the designed direction.

Multiple conductors can be provided to produce a multi-phase inductive element, depending on the regulatory requirements of the two or three phase power applied to the power inductor.

The invention also relates to an inductance element, which comprises a lead and a magnet, wherein two ends of the lead are exposed out of the magnet, the magnet comprises iron-based magnetic powder particles, the iron-based magnetic powder particles are coated with a composite insulating layer of ferrite and silicon dioxide, and the inductance element can keep the efficiency at 500-960 ℃, preferably 700-900 ℃.

The ferrite and silicon dioxide composite insulating layer can bear the high temperature of 960 ℃ at most, so that the inductance element can be stably used in a higher-temperature working state.

Furthermore, the surface of the lead is coated with a nano composite insulating layer, and nano oxides are uniformly distributed on the nano composite insulating layer.

The nano oxide can bear the high temperature of 700 ℃ without changing the characteristics, so that the inductance element can be stably used in a higher-temperature working state, and when the thickness of the nano composite insulation layer is thin, the direct-current voltage resistance of the inductance can be obviously improved under the condition of not influencing the inductance.

Further, the inductance element is coated with a layer of resin.

The resin bonds the iron-based magnetic powder together, so that the mechanical strength of the inductor can be greatly improved, the inductance cannot be reduced or the power consumption of the inductor cannot be increased, different types of resin can obtain different bending strength and tensile strength combinations, and the types of the resin can be selected according to the use scene of the inductor.

Furthermore, a wire slot extending from one end of the magnet to the other end of the magnet is arranged in the magnet, the wire is inserted into the wire slot, and the two ends of the wire are exposed out of the wire slot; the two ends of the wire are connected with electrode pins, the top surface edges of the two ends of the magnet are provided with wire grooves for containing the electrode pins, and the width of each wire groove is equal to that of the magnet; the electrode pin is formed by bending two ends of a conducting wire exposed outside the magnet, the two ends of the conducting wire are symmetrically attached to the surface of the magnet, and the width of the two end parts of the conducting wire is larger than that of the middle part of the conducting wire.

The width of the wire groove is set to be equal to the width of the magnet, so that the problem that the right-angle position of the traditional inner right-angle wire groove is subjected to processing stress and microcracks are easily generated when the wire groove is pressed is solved. The I-shaped wire formed by integrally blanking can increase the welding area of the welding pad, reduce the contact resistance and increase the welding strength. Because the post-processing procedures such as edging, welding and the like do not exist, the method has high reliability and is suitable for severe scenes such as vehicle-mounted scenes. The length of the wire slot can be reduced by increasing the width of the wire slot, so that the magnetic path sectional area of the inductor is increased, the inductance and saturation current of the inductor can be improved in a limited way, and the power consumption of the inductor is reduced.

Furthermore, a wire slot extending from one end of the magnet to the other end of the magnet is arranged in the magnet, the wire is inserted into the wire slot, and the two ends of the wire are exposed out of the wire slot; the two ends of the wire are connected with electrode pins, the top surface edges of the two ends of the magnet are provided with wire grooves for containing the electrode pins, and the width of each wire groove is equal to that of the magnet; the electrode pins are prefabricated by bending the middle parts of the tinned wires, and are bent to form a first bent pin and a second bent pin; a first folding leg of the electrode pin is provided with a pin fixing groove, two ends of the lead can be inserted into the pin fixing groove on the first folding leg of the electrode pin and welded in the pin fixing groove through brazing or laser, and a second folding leg of the electrode pin can be tightly attached to a wire groove of the magnet; the width of the second folded leg is larger than that of the conducting wire, and the width of the second folded leg is smaller than or equal to that of the magnet.

The width of the wire groove is set to be equal to the width of the magnet, so that the problem that the right-angle position of the traditional inner right-angle wire groove is subjected to processing stress and microcracks are easily generated when the wire groove is pressed is solved. When the lead is thicker, the electrode pin is manufactured in advance because the magnet is easily damaged in the turnover process, then the electrode pin and the lead of the inductor exposing the magnet are assembled, the electrode pin and the lead are positioned through the fit clearance of the electrode pin and the lead of the inductor exposing the magnet, and the electrode pin and the lead are mechanically and electrically connected through welding technologies such as brazing or laser welding. The second folded leg with larger width can increase the welding area of the welding pad, reduce the contact resistance and increase the welding strength. The length of the wire slot can be reduced by increasing the width of the wire slot, so that the magnetic path sectional area of the inductor is increased, the inductance and saturation current of the inductor can be improved in a limited way, and the power consumption of the inductor is reduced.

Further, the magnet consists of a prefabricated bottom blank and a top blank; the conducting wire is placed on the prefabricated bottom blank, and two ends of the conducting wire are exposed out of the prefabricated bottom blank; the top surface of the prefabricated bottom blank is provided with a limit wire groove parallel to the length direction of the prefabricated bottom blank, the middle part of the wire is arranged in the limit wire groove, and the two sides of the wire are abutted against the two side walls of the limit wire groove; the prefabricated bottom blank can be matched with the top blank to compress the conducting wire.

Drawings

FIG. 1 is a drawing for explaining embodiment 13 of the present invention.

FIG. 2 is a diagram illustrating embodiment 14 of the present invention.

FIG. 3 is a diagram illustrating embodiment 15 of the present invention.

Fig. 4 is an exploded view of example 15 of the present invention.

Fig. 5 is an explanatory view of the magnet of the present invention.

In the figure: the device comprises a magnet 1, a wire groove 11, a prefabricated bottom blank 12, a limiting wire groove 121 and a top blank 13; wire 2, wire end 21; the electrode lead 3, the first folded leg 31, the lead fixing groove 311, and the second folded leg 32.

Detailed Description

Various aspects of the present invention will be described in detail below, but the present invention is not limited to these specific embodiments. Modifications and adaptations of the present invention that come within the spirit of the following disclosure may be made by those skilled in the art and are within the scope of the present invention.

The inventors of the present invention have made extensive and intensive studies to develop a method for manufacturing an inductance component, which has advantages of high inductance, low power consumption, high temperature resistance, high dc voltage resistance, high bending strength, high tensile strength, and rust prevention.

Surface film-forming reaction of magnetic powder

The prior art iron-based magnetic powder is classified into iron nickel powder, iron silicon powder, carbonyl iron powder, iron silicon aluminum powder, iron silicon chromium powder, amorphous powder and nanocrystalline powder, the inventor selects FeNi50 powder which is commonly produced by gas atomization, takes FeNi50 powder which does not undergo surface film forming reaction as a comparison group and FeNi50 powder which does undergo surface film forming reaction as an implementation group, and under the condition that other preparation processes are the same, inductance elements are respectively prepared at the annealing temperatures of 300 ℃, 400 ℃, 500 ℃, 600 ℃, 700 ℃, 800 ℃, 900 ℃, 960 ℃ and 1000 ℃, and the inductance, the power consumption and the direct current voltage resistance of the inductance elements are respectively measured.

Comparison group

Preparation of magnetic powder for pressing

Mixing FeNi50 powder prepared by gas atomization with the weight ratio of +200 meshes 5%, 200 to +325 meshes 25%, 325 to +800 meshes 45% and the balance of-800 meshes to prepare raw powder. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to prepare secondary powder, screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

secondly, compression molding is carried out

Filling the magnetic powder for pressing prepared in the step one into a 4x10x2mm mould, and placing a copper wire with the thickness of 0.5x2.0x18mm in the mould, wherein two ends of the copper wire are clamped in the mould and exposed out of the magnetic powder for pressing. Pressing with 1600MPa pressure, keeping the pressure for 0.5s, and finally demoulding to obtain an inductance pressed blank with the copper wire and the magnetic powder for pressing integrated;

third, high temperature heat treatment

The method comprises the following steps of putting an inductance pressed compact into an atmosphere furnace for heat treatment, wherein the heat treatment temperature mainly comprises two main stages of preheating and annealing, the preheating temperature is 150 ℃, the holding time is 80 min, and the main purpose is to avoid magnet cracking caused by rapid volatilization of a lubricant, the annealing temperature is respectively 300 ℃, 400 ℃, 500 ℃, 600 ℃, 700 ℃, 800 ℃, 900 ℃, 960 ℃, 1000 ℃, and the holding time is 20 min, so that the processing stress generated during pressing is eliminated, the magnetic conductivity is improved, and the magnetic loss is reduced, and pure nitrogen is used as a protective atmosphere.

Group of embodiments

Preparation of magnetic powder for pressing

Mixing FeNi50 powder prepared by gas atomization with the weight ratio of +200 meshes 5%, 200 to +325 meshes 25%, 325 to +800 meshes 45% and the balance of-800 meshes to prepare raw powder. Adding raw powder into phosphoric acid: silane coupling agent: water = 0.5: 0.5: 99 phosphoric acid and silane coupling agent are subjected to surface film forming reaction in an aqueous solution, the reaction temperature is 100 ℃, and the reaction time is 0.5 h. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

secondly, compression molding is carried out

third, high temperature heat treatment

Inductance of 100kHz/1V of the inductance elements prepared in the comparative group and the practical group was measured by a 3255B LCR analyzer, power consumption of 500kHz/50mT was measured by a SY8219 BH analyzer, and direct current voltage resistance of the inductance was measured by a 3153 HIPOT tester (DC range 50-200V), and the measurement results are shown in Table 1.

TABLE 1

The iron-based magnetic powder can generate plastic deformation to generate dislocation and slippage of a grain boundary when being extruded by large pressing pressure, so that the internal stress of a magnet is increased to influence the rotation of a magnetic domain, the magnetic performance is deteriorated, the pressing stress can be eliminated through annealing heat treatment, the higher the annealing temperature is, the better the stress removing effect is, when the annealing temperature exceeds the Curie temperature of the magnetic powder, the pressing stress can be completely eliminated in a close way, and the best magnetic performance can be obtained. When the metal powder is coated by the silicone resin, the silicone resin can be converted into a glass state under the low-temperature baking condition to realize the insulation coating of the magnetic powder, but the decomposition temperature point of the hydrocarbon oxygen group of the silicone resin is far lower than the Curie temperature of most iron-based magnetic powder. The best performance of the magnetic powder cannot be achieved by using annealing conditions far below the curie temperature, and the magnetic powder is degraded by breaking the glassy coating layer due to gas escaping from the magnet when annealed at a high temperature of more than 500 ℃.

According to the invention, phosphoric acid and a silicon-based insulating agent are used for insulating iron-based magnetic powder, a ferrous phosphate and silicon dioxide composite insulating layer generated by reaction can bear the high temperature of 960 ℃, when the annealing temperature reaches 1000 ℃, the insulating layer is damaged, the loss of a magnet is increased violently, and the inductance performance is deteriorated. 960 c already covers the curie temperature of most iron-based magnetic powders, so optimum electromagnetic properties are obtained using the magnetic powder insulation method of the present invention, and the preferred annealing temperature can be selected according to the different performance requirements of the inductor.

Surface insulation treatment of wire

On the basis of the implementation group process, the inventor synthesizes the optimal balance values of inductance, magnet loss and withstand voltage, selects the annealing temperature of 700 ℃, and immerses a pure copper wire into a silicon hydride coupling agent and alcohol according to the weight ratio of 1:4 for 5min, taking out and draining residual liquid on the surface, and respectively immersing the nano silicon dioxide: nano aluminum oxide: sodium silicate = 2: 2: 96. 5: 2: 93. 2: 5: 93. 5: 5: 90 for 1min, taking out, putting into an oven at 80 ℃ and baking to obtain insulated copper wires with different insulation degrees so as to carry out surface insulation treatment on the copper wires and form a nano composite insulating layer on the surfaces of the wires. And comparing the inductor without copper wire insulation as a comparison group 1 and the copper wire insulated by common resin paint as a comparison group 2, and respectively measuring the power consumption and the direct-current voltage resistance of the inductor elements. The specific implementation steps are as follows:

preparation of magnetic powder for pressing

second, copper wire surface insulation treatment

Pure copper wire of 0.5 × 2.0 × 18mm is immersed in a solution of silane coupling agent and alcohol in a weight ratio of 1:4 for 5min, taking out and draining residual liquid on the surface, and respectively immersing the nano silicon dioxide: nano aluminum oxide: sodium silicate = 2: 2: 96. 5: 2: 93. 2: 5: 93. 5: 5: soaking the 90 aqueous suspension for 1min, taking out, and putting into an oven at 80 ℃ for baking to obtain an insulated copper wire;

thirdly, compression molding forming

And (3) filling the magnetic powder for pressing prepared in the first step into a 4x10x2mm mould, placing the insulated copper wire obtained in the second step into the mould, and clamping two ends of the copper wire in the mould to be exposed out of the magnetic powder for pressing. Pressing with 1600MPa pressure, keeping the pressure for 0.5s, and finally demoulding to obtain an inductance pressed blank with the copper wire and the magnetic powder for pressing integrated;

fourth, high temperature heat treatment

The method comprises the following steps of putting an inductance pressed compact into an atmosphere furnace for heat treatment, wherein the heat treatment temperature mainly comprises two main stages of preheating and annealing, the preheating temperature is 150 ℃, the holding time is 80 min, the main purpose is to avoid cracking of a magnet caused by rapid volatilization of a lubricant, the annealing temperature is 700 ℃, the holding time is 20 min, the processing stress generated during pressing is eliminated, the magnetic conductivity is improved, and the magnetic loss is reduced, and pure nitrogen is used as a protective atmosphere.

Fifth, fold the whole pin

Bending two ends of the lead exposed outside the magnet, enabling the two ends of the lead to be symmetrically attached to the surface of the magnet to form electrode pins, removing the insulating layer on the surface of the lead by mechanical polishing or laser etching, and then carrying out tin immersion or tin plating on the pins to form the inductor.

Inductance of 100kHz/1V of the inductance elements prepared in the comparative group and the practical group was measured by a 3255B LCR analyzer, power consumption of 500kHz/50mT was measured by a SY8219 BH analyzer, and direct current voltage resistance of the inductance was measured by a 3153 HIPOT tester (DC range 50-200V), and the measurement results are shown in Table 2.

TABLE 2

The conventional copper wire is wrapped on the surface of the copper wire by using resin paint for insulation, the resin paint can be only used at a low temperature of below 200 ℃, carbonization is carried out after annealing at 700 ℃ so as to lose the insulation effect, volatile matters during carbonization penetrate into magnetic powder particles, the insulation property between the powder is reduced, and the inductance power consumption is increased and the inductance is reduced. According to the invention, the nano silicon dioxide is adsorbed on the surface of the copper wire, and the nano aluminum oxide is added to fully disperse the nano silicon dioxide in the suspension, so that the nano silicon dioxide is adsorbed on the surface of the copper wire more uniformly, a nano composite insulating layer is formed on the surface of the wire, the nano oxide can bear 700 ℃ annealing without changing the characteristics, and when the thickness of the nano composite insulating layer is thin, the direct current voltage resistance of the inductor can be obviously improved under the condition of slightly reducing the inductance.

Impregnated resin

On the basis of the implementation group process, the inventor selects nano silicon dioxide: nano aluminum oxide: sodium silicate = 5: 2: 93 carrying out surface insulation treatment on the copper wire by using aqueous suspension, respectively soaking the inductor subjected to heat treatment in epoxy resin, phenolic resin, furan resin, alkyd resin and silicon resin for 1h, taking out the inductor, washing away the residual resin on the surface by using an organic solvent, putting the inductor into an oven, baking and curing at 180 ℃ for 3h in a protective atmosphere of nitrogen to prepare inductor elements, and respectively measuring the inductance, the power consumption, the direct-current voltage resistance, the bending strength and the tensile strength of the inductor elements. The specific implementation steps are as follows:

preparation of magnetic powder for pressing

second, copper wire surface insulation treatment

Pure copper wire of 0.5 × 2.0 × 18mm is immersed in a solution of silane coupling agent and alcohol in a weight ratio of 1:4 for 5min, taking out, draining residual liquid on the surface, and immersing in nano silicon dioxide: nano aluminum oxide: sodium silicate = 5: 2: 93 for 1min, taking out, and putting into an oven at 80 ℃ for baking to obtain insulated copper wires with different insulation degrees;

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

And respectively soaking the inductor subjected to heat treatment in epoxy resin, phenolic resin, furan resin, alkyd resin and silicon resin for 1h, taking out the inductor, cleaning the residual resin on the surface by using an organic solvent, and putting the inductor into an oven for baking and curing at 180 ℃ for 3h under the protective atmosphere of nitrogen.

Sixth, fold the whole pin

The inductance of the inductance element prepared in the comparison group and the implementation group is 100kHz/1V by using a 3255B LCR analyzer, the power consumption of 500kHz/50mT is tested by using a SY8219 BH analyzer, the direct current resistant voltage of the inductance is tested by using a 3153 HIPOT tester (the DC range is 50-200V), the bending strength and the tensile strength of samples prepared by different types of resins are tested by using an SD2000 universal material testing machine, and the measurement results are shown in Table 3.

TABLE 3

The binder and the release agent in the magnetic powder for pressing contain hydrocarbon-oxygen groups, and can be decomposed into gas to leave the interior of the inductor in the annealing process at 700 ℃, and a large number of fine pores can be left in the interior of the magnet due to the decomposition of the binder and the release agent. The inductor is immersed in the resin, and the resin is absorbed into the magnet under the action of capillary force to fill the pores in the magnet. The resin in the pores is cured through high-temperature baking, the cured resin bonds the magnetic powder for pressing together, the mechanical strength of the inductor can be greatly improved, the inductance can not be reduced or the power consumption of the inductor can not be increased, different types of resin can obtain different bending strength and tensile strength combinations, and the types of the resin can be selected according to the use scene of the inductor.

Surface spray coating

The inventor selects epoxy resin as impregnating resin on the basis of the implementation group process, improves the voltage-resistant grade and the rust-resistant grade of the inductor by spraying a coating on the surface of the inductor, preheats the inductor to 150 ℃, sprays at least one of a layer of 0.02-0.1mm thick alkyd varnish, epoxy paint, novolac and epoxy polyester novolac on the surface of the inductor, and prepares inductor elements by baking and curing at 150 ℃ after spraying, and respectively measures the direct-current resistant voltage of the inductor elements and performs a neutral salt spray test. The specific implementation steps are as follows:

preparation of magnetic powder for pressing

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

And soaking the inductor after heat treatment in epoxy resin for 1h, taking out the inductor, cleaning the residual resin on the surface by using an organic solvent, and baking and curing the inductor in an oven at 180 ℃ for 3h under the protective atmosphere of nitrogen.

Sixth, protect the wire

And covering and protecting the lead wires exposed out of the magnet part by using a high-temperature adhesive tape, or protecting the exposed lead wires by using an immersion agent.

Seventh, spray coating

Preheating the inductor to 150 ℃, spraying at least one of a layer of 0.02-0.1mm thick gray alkyd paint, epoxy paint, phenolic varnish and epoxy polyester phenolic paint on the surface of the inductor, and baking and curing at 150 ℃ after spraying.

Eighthly, cleaning the conducting wire

And removing the protective wire in the seventh step by using a high-temperature adhesive tape or a release agent, and completely cleaning the attachments on the surface of the wire.

Nine, roll over whole pin

The direct current resistant voltage of the inductor is tested by using a 3153 HIPOT tester (the DC range is 50-200V), the inductor is placed in a saline spray device with the temperature of 35 +/-3 ℃, the pH value of 6.5-7.2 and the temperature of 5 +/-0.5% of sodium chloride to carry out a neutral salt spray test, the surface corrosion area of the inductor is observed after 8 hours, and the measurement result is shown in Table 4.

TABLE 4

Example 1:

preparation of magnetic powder for pressing

second, copper wire surface insulation treatment

Pure copper wire of 0.5 × 2.0 × 18mm is immersed in a solution of silane coupling agent and alcohol in a weight ratio of 1:4 for 5min, taking out, draining residual liquid on the surface, and immersing in nano silicon dioxide: nano aluminum oxide: the weight ratio of the sodium silicate = 5: 2: 93 for 1min, taking out, and putting into an oven at 80 ℃ for baking to obtain insulated copper wires with different insulation degrees;

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Example 2:

preparation of magnetic powder for pressing

Mixing FeNi50 powder prepared by gas atomization with the weight ratio of +200 meshes 5%, 200 to +325 meshes 25%, 325 to +800 meshes 45% and the balance of-800 meshes to prepare raw powder. Adding raw powder into a mixture of chromic acid, a silane coupling agent and water in a weight ratio of (0.5): 1.5: 98 chromic acid and silane coupling agent water solution to carry out surface film forming reaction, the reaction temperature is 130 ℃, and the reaction time is 0.3 h. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Example 3:

preparation of magnetic powder for pressing

Mixing FeNi50 powder prepared by gas atomization with the weight ratio of +200 meshes 5%, 200 to +325 meshes 25%, 325 to +800 meshes 45% and the balance of-800 meshes to prepare raw powder. Adding raw powder into potassium silicate: silane coupling agent: water = 1: 1: 98 potassium silicate and silane coupling agent in water solution to carry out surface film forming reaction at 110 deg.c for 1 hr. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Example 4:

preparation of magnetic powder for pressing

Mixing FeNi50 powder prepared by gas atomization with the weight ratio of +200 meshes 5%, 200 to +325 meshes 25%, 325 to +800 meshes 45% and the balance of-800 meshes to prepare raw powder. Adding zinc borate, a silane coupling agent and water in a weight ratio of (1): 2: 97 and the aqueous solution of the silane coupling agent are subjected to surface film forming reaction at the temperature of 80 ℃ for 0.5 h. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Comparative example 1

Preparation of magnetic powder for pressing

secondly, compression molding is carried out

third, high temperature heat treatment

The method comprises the following steps of putting an inductance pressed compact into an atmosphere furnace for heat treatment, wherein the heat treatment temperature mainly comprises two main stages of preheating and annealing, the preheating temperature is 150 ℃, the holding time is 80 min, the main purpose is to avoid cracking of a magnet caused by rapid volatilization of a lubricant, the annealing temperature is 500 ℃, the holding time is 20 min, the processing stress generated during pressing is eliminated, the magnetic conductivity is improved, and the magnetic loss is reduced.

Example 5:

preparation of magnetic powder for pressing

The FeSi9.6Al5.7 powder prepared by gas atomization is mixed according to the weight ratio of +200 meshes 5%, -200 to +325 meshes 40%, -325 to +800 meshes 45%, and the balance is-800 meshes to prepare the original powder. Adding raw powder into phosphoric acid in a weight ratio: silane coupling agent: water = 0.5: 0.5: 99 phosphoric acid and silane coupling agent are subjected to surface film forming reaction in an aqueous solution, the reaction temperature is 100 ℃, and the reaction time is 0.5 h. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Example 6:

preparation of magnetic powder for pressing

The FeSi9.6Al5.7 powder prepared by gas atomization is mixed according to the weight ratio of +200 meshes 5%, -200 to +325 meshes 40%, -325 to +800 meshes 45%, and the balance is-800 meshes to prepare the original powder. Adding raw powder into chromic acid: silane coupling agent: water = 0.5: 1.5: 98 chromic acid and silane coupling agent water solution to carry out surface film forming reaction, the reaction temperature is 130 ℃, and the reaction time is 0.3 h. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Example 7:

preparation of magnetic powder for pressing

The FeSi9.6Al5.7 powder prepared by gas atomization is mixed according to the weight ratio of +200 meshes 5%, -200 to +325 meshes 40%, -325 to +800 meshes 45%, and the balance is-800 meshes to prepare the original powder. Adding the raw powder into potassium silicate according to the weight ratio; a silane coupling agent; water = 1: 1: 98 potassium silicate and silane coupling agent in water solution to carry out surface film forming reaction at 110 deg.c for 1 hr. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Example 8:

preparation of magnetic powder for pressing

The FeSi9.6Al5.7 powder prepared by gas atomization is mixed according to the weight ratio of +200 meshes 5%, -200 to +325 meshes 40%, -325 to +800 meshes 45%, and the balance is-800 meshes to prepare the original powder. Adding raw powder into zinc borate in a weight ratio: silane coupling agent: water = 1: 2: 97 and the aqueous solution of the silane coupling agent are subjected to surface film forming reaction at the temperature of 80 ℃ for 0.5 h. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Comparative example 2

Preparation of magnetic powder for pressing

The FeSi9.6Al5.7 powder prepared by gas atomization is mixed according to the weight ratio of +200 meshes 5%, -200 to +325 meshes 40%, -325 to +800 meshes 45%, and the balance is-800 meshes to prepare the original powder. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to prepare secondary powder, screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

secondly, compression molding is carried out

third, high temperature heat treatment

Example 9:

preparation of magnetic powder for pressing

FeSi5.5Cr5 powder prepared by water atomization is mixed according to the weight ratio of-200 to +325 meshes to 10 percent, 325 to +800 meshes to 45 percent and the balance to 800 meshes to prepare the original powder. Adding raw powder into a mixture with the weight ratio of 0.5: 0.5: 99 phosphoric acid, silane coupling agent and water solution are subjected to surface film forming reaction at the temperature of 100 ℃ for 0.5 h. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Example 10:

preparation of magnetic powder for pressing

FeSi5.5Cr5 powder prepared by water atomization is mixed according to the weight ratio of-200 to +325 meshes to 10 percent, 325 to +800 meshes to 45 percent and the balance to 800 meshes to prepare the original powder. Adding raw powder into chromic acid: silane coupling agent: water = 0.5: 1.5: 98 chromic acid and silane coupling agent water solution to carry out surface film forming reaction, the reaction temperature is 130 ℃, and the reaction time is 0.3 h. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Example 11:

preparation of magnetic powder for pressing

FeSi5.5Cr5 powder prepared by water atomization is mixed according to the weight ratio of-200 to +325 meshes to 10 percent, 325 to +800 meshes to 45 percent and the balance to 800 meshes to prepare the original powder. Adding raw powder into potassium silicate: silane coupling agent: water = 1: 1: 98 potassium silicate and silane coupling agent in water solution to carry out surface film forming reaction at 110 deg.c for 1 hr. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Example 12:

preparation of magnetic powder for pressing

FeSi5.5Cr5 powder prepared by water atomization is mixed according to the weight ratio of-200 to +325 meshes to 10 percent, 325 to +800 meshes to 45 percent and the balance to 800 meshes to prepare the original powder. Adding raw powder into zinc borate in a weight ratio of: silane coupling agent: water = 1: 2: 97 and the aqueous solution of the silane coupling agent are subjected to surface film forming reaction at the temperature of 80 ℃ for 0.5 h. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to obtain secondary powder; screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

second, copper wire surface insulation treatment

thirdly, compression molding forming

fourth, high temperature heat treatment

Fifthly, impregnating resin

Sixth, fold the whole pin

Comparative example 3

Preparation of magnetic powder for pressing

FeSi5.5Cr5 powder prepared by water atomization is mixed according to the weight ratio of-200 to +325 meshes to 10 percent, 325 to +800 meshes to 45 percent and the balance to 800 meshes to prepare the original powder. Mixing silicon resin and alcohol according to a weight ratio of 1:15 to prepare a silicon resin solution, and mixing the raw powder and the silicon resin solution according to a weight ratio of 1: 0.015 mixing, coating the original powder with silicone resin to prepare secondary powder, screening granulated powder with the granularity of 80-200 meshes in the secondary powder, and adding a mixture of calcium stearate and zinc stearate with the weight ratio of 0.2% as a lubricant to obtain magnetic powder for pressing;

secondly, compression molding is carried out

third, high temperature heat treatment

The inventors measured inductance, 60A superimposed inductance, magnetic permeability, magnetic loss, dc voltage resistance, compressive strength, and flexural strength of the magnetic loss inductance components prepared in examples 1 to 12 and comparative examples 1 to 3, respectively, and the measurement results are shown in table 5.

TABLE 5

Example 13

As shown in fig. 1, an inductance element includes a magnet 1 and a wire 2, the magnet 1 includes iron-based magnetic powder particles with different particle sizes, the iron-based magnetic powder particles are coated with a composite insulating layer of ferrite and silicon dioxide, the surface of the wire 2 is coated with an insulating protective layer, the surface of the wire 2 is coated with a nano composite insulating layer, the nano composite insulating layer is uniformly distributed with nano oxides, and the inductance element is coated with a layer of resin. The magnet 1 is substantially rectangular parallelepiped, and the area of the long and high plane is smaller than that of the long and wide plane. A wire slot which extends from one end of the magnet 1 to the other end of the magnet 1 is arranged in the magnet 1, and the wire slot is parallel to the length direction of the magnet 1. The wire 2 is inserted into the wire slot, the middle part of the wire 2 is arranged in the wire slot, and two notches of the wire slot are exposed at two ends of the wire 2. Two ends of the lead 2 exposed outside the magnet 1 are bent, so that the two ends of the lead 2 are symmetrically attached to the top surface of the magnet 1 to form electrode pins. And mechanically polishing the surface of the electrode pin or etching the surface of the electrode pin by laser, removing the insulating protective layer on the surface of the lead 2, and then carrying out tin immersion or tin plating on the electrode pin. The top surface of the magnet 1 is provided with a wire groove 11 for mounting electrode pins, and two ends of the lead 2 are tightly attached to the wire groove 11 of the magnet 1.

Example 14

As shown in fig. 2, an inductance element includes a magnet 1 and a wire 2, the magnet 1 includes iron-based magnetic powder particles with different particle sizes, the iron-based magnetic powder particles are coated with a composite insulating layer of ferrite and silicon dioxide, the surface of the wire 2 is coated with an insulating protective layer, the surface of the wire 2 is coated with a nano composite insulating layer, the nano composite insulating layer is uniformly distributed with nano oxides, and the inductance element is coated with a layer of resin. The magnet 1 is substantially rectangular parallelepiped, and the area of the long and high plane is smaller than that of the long and wide plane. A wire slot which extends from one end of the magnet 1 to the other end of the magnet 1 is arranged in the magnet 1, and the wire slot is parallel to the length direction of the magnet 1. The wire 2 is inserted into the wire slot, the middle part of the wire 2 is arranged in the wire slot, and two notches of the wire slot are exposed at two ends of the wire 2. The two ends of the wire 2 exposed out of the notch of the wire slot can be folded upwards to extend to the outer sides of the two ends of the magnet 1. And two ends of the lead 2 exposed outside the magnet 1 are bent, so that the two ends of the lead 2 are symmetrically attached to the top surface of the magnet 1 to form electrode pins, and after the surface of the electrode pins is mechanically polished or etched by laser, the insulating protective layer on the surface of the lead 2 is removed, and then the electrode pins are subjected to tin immersion or tin plating.

In this embodiment, the width of the slot 11 on the top surface of the magnet 1 is equal to the width of the magnet 1. Such an embodiment is more convenient to manufacture than prior art embodiments. The wire casing 11 is also formed by pressing while the magnet 1 is pressed, and the right-angle position of the traditional inner right-angle wire casing has processing stress when the magnet 1 is pressed in the prior art, so that microcracks are easily generated on the magnet 1. Since the electrode pins are closely attached in the slot 11 of the magnet 1, in order to have a larger soldering area when the inductor is soldered to a circuit board, the width of the electrode pins at the two end portions 21 of the wire 2 is larger than the width of the middle portion of the wire 2, and even the width of the electrode pins at the two end portions 21 of the wire 2 may be equal to the width of the slot 11. The length of the wire slot 11 can be reduced by increasing the width of the wire slot 11, so that the magnetic path sectional area of the inductor is increased, the inductance and saturation current of the inductor can be improved in a limited way, and the power consumption of the inductor is reduced.

Example 15

As shown in fig. 3, 4 and 5, an inductance element includes a magnet 1 and a wire 2, the magnet 1 includes iron-based magnetic powder particles with different particle sizes, the iron-based magnetic powder particles are coated with a composite insulating layer of ferrite and silicon dioxide, the surface of the wire 2 is coated with a nano composite insulating layer, nano oxides are uniformly distributed on the nano composite insulating layer, and a layer of resin is coated outside the inductance element. The magnet 1 is substantially rectangular parallelepiped, and the area of the long and high plane is smaller than that of the long and wide plane. A wire slot which extends from one end of the magnet 1 to the other end of the magnet 1 is arranged in the magnet 1, and the wire slot is parallel to the length direction of the magnet 1. The wire 2 is inserted into the wire slot, the middle part of the wire 2 is arranged in the wire slot, and two notches of the wire slot are exposed at two ends of the wire 2.

As shown in fig. 5, the magnet 1 is composed of a prefabricated bottom blank 12 and a top blank 13, the prefabricated bottom blank 12 is provided with a limiting wire groove 121, i.e. the aforementioned wire slot, the middle part of the wire 2 can be placed in the limiting wire groove 121, and two ends of the wire are exposed out of the prefabricated bottom blank 12. The limiting wire groove 121 can clamp the wire 2. In the actual manufacturing process, the machining mode can cause one end of the prefabricated bottom blank 12 to be slightly higher than the other end, and one end of the top blank 13 to be slightly higher than the other end, so that in order to eliminate the machining error, when the prefabricated bottom blank 12 and the bottom blank are pressed, the higher end of the prefabricated bottom blank 12 and the lower end of the top blank 13 are placed on the same side for pressing. The top preform 13 may be press-molded by filling an insulating magnetic powder in a pressing groove where the prefabricated bottom preform 12 and the wire 2 are placed and applying pressure to the insulating magnetic powder at a high temperature. The top blank 13 formed by pressing and forming can be matched with the prefabricated bottom blank 12 to form the magnet 1; the top blank 13 may be formed by pressing insulating magnetic powder alone, and then placed in a pressing groove to be matched with the prefabricated bottom blank 12 at a high temperature to be pressed into the magnet 1.

In the embodiment of the present embodiment regarding the heights of the two side walls of the position-limiting wire groove 121, when the heights of the two side walls of the position-limiting wire groove 121 are smaller than the height of the wire 2, the bottom surface of the top blank 13 is provided with a position-limiting supplementary groove corresponding to the position-limiting wire groove 121, so that the prefabricated bottom blank 12 and the top blank 13 can press the wire 2; when the heights of the two side walls of the limiting lead groove 121 are equal to the height of the lead 2, the bottom surface of the top blank 13 is a plane; when the heights of the two side walls of the limiting conductor groove 121 are greater than the height of the conductor 2, the bottom surface of the top blank 13 is provided with a limiting groove filling block corresponding to the limiting conductor groove 121 on the prefabricated bottom blank 12, so that the prefabricated bottom blank 12 and the top blank 13 can compress the conductor 2.

As shown in fig. 5, the magnet 1 is formed by pressing a prefabricated bottom blank 12 and a top blank 13. When the thickness of the lead 2 is thinner, the two end parts of the lead 2 are integrally connected with the electrode pins, and the two end parts of the lead 2 are exposed out of the lead slot and are turned over to the top surface of the magnet 1, so that the two ends of the lead 2 are symmetrically attached to the top surface of the magnet 1 to form the electrode pins; however, when the lead 2 is thicker, as shown in fig. 3, since the lead 2 is thicker during the folding process and the press-fit structure of the magnet 1 is easily damaged, the electrode pins are pre-manufactured, and then the electrode pins and the lead 2 of the inductor exposed out of the magnet 1 are assembled.

In the embodiment, the tinned lead 2 is punched and bent to manufacture the electrode pin to be connected, the lead 2 of the inductor exposed out of the magnet 1 is assembled with the electrode pin, the positioning is carried out through the fit clearance between the lead 2 and the electrode pin and the tool fixture, and the mechanical and electrical connection is carried out through welding technologies such as brazing or laser welding. The top surface of the magnet 1 is provided with a wire groove 11 for installing an electrode pin, and the middle part of the electrode pin is bent to form a first bending pin 31 and a second bending pin 32; the first folding leg 31 of the electrode leg is provided with a leg fixing groove 311, two ends of the wire 2 can be inserted into the leg fixing groove 311 of the first folding leg 31 of the electrode leg and soldered or laser welded in the leg fixing groove 311, and the second folding leg 32 of the electrode leg can be closely attached to the wire groove 11 of the magnet 1. The width of the second folded leg 32 is greater than the width of the lead 2, and the width of the second folded leg 32 is less than or equal to the width of the magnet 1. The width of the second folding leg 32 is set to be larger, so that the inductor has a larger welding area when being welded on a circuit board, and meanwhile, in order to ensure that the second folding leg 32 is tightly attached to the wire groove 11, the width of the second folding leg 32 is smaller than or equal to the width of the magnet 1.

Claims

1. a manufacturing method of an inductance element, is characterized in that, comprises the following steps:

S1c. The iron-based magnetic powder is subjected to a surface film-forming reaction to form a composite insulating layer of ferrous salt and silicon dioxide on the surface. After the proportion is mixed, the magnetic powder for pressing is obtained;

S2c, place the wire in the mold;

S3c, filling the magnetic powder for pressing into the mold, so that both ends of the wire are exposed to the magnetic powder for pressing, and pressing to make the wire and the magnetic powder for pressing become one, and then demoulding to obtain an integrated inductance compact;

S4c, after high-temperature heat treatment is performed on the inductor green compact, an inductor element is made.

2 . The method for manufacturing an inductance element according to claim 1 , wherein the surface film-forming reaction in the step S1c is to add iron-based magnetic powder to phosphoric acid, phosphate, chromic acid, chromate, silicate, At least one of sulfate and borate undergoes a surface film-forming reaction in an aqueous solution of a silane coupling agent.

3. The method for manufacturing an inductance element according to claim 2, further comprising the steps of:

S2a, performing surface insulation treatment on the wires in the step S2c using nano-oxides to form a nano-composite insulating layer on the surface of the wires, and the nano-composite insulating layers are uniformly distributed with nano-oxides.

4. The method for manufacturing an inductance element according to claim 3, wherein in the step S2a, the wire is a copper wire, and the surface insulation treatment is to immerse the copper wire in the silane coupling agent and the diluent in a weight ratio of 1:2 ~10, preferably 1:4 ~ 6 mixed solution 2 ~ 10min, preferably 2 ~ 5min, after taking out and draining the residual liquid on the surface, put into the aqueous suspension of nano-silicon dioxide, nano-aluminum oxide, sodium silicate, Preferably, the weight ratio of nano-silicon dioxide: nano-alumina: sodium silicate=2~5:2~5:90~96 is soaked in the aqueous suspension for 1-3min, then taken out and put into 60~100 ℃, preferably 70 It is dried in an oven at ~80°C, and a nanocomposite insulating layer is formed on the surface of the wire, and the nanocomposite insulating layer is uniformly distributed with nano oxides.

5. The method for manufacturing an inductance element according to any one of claims 1-4, wherein the high-temperature heat treatment in step S4c includes two stages of preheating and annealing, the preheating temperature is 100-300°C, and the holding time is ≥30min, annealing temperature is 500～960 ℃, preferably 650～800 ℃, preferably 700～750 ℃ again, hold time 10～40min, preferably 20～30min, use at least one in nitrogen, hydrogen, argon as protective atmosphere , or vacuum <0.1Pa, preferably <0.02Pa.

6. The method for manufacturing an inductance element according to claim 5, further comprising the steps of:

S5c, immerse the inductance element after high temperature heat treatment in resin for 0.2~3h, preferably 0.5~1h, after taking out the inductance element, use an organic solvent to wash off the residual resin on the surface, and put it into an oven to bake and cure for 1~3h under a protective gas atmosphere , this step is preferably carried out under the condition of vacuum <1Pa.

7. The method for manufacturing an inductance element according to claim 6, further comprising the steps of:

S2b, pressing the magnetic powder used in the pressing step S1c into a prefabricated base blank, the prefabricated base blank is provided with a limit wire groove, and the copper wire processed in the step S2a is placed in the limit wire groove according to the designed direction;

In the step S2c, the assembled prefabricated base blank and the copper wire are placed on the bottom of the mold.

8. The method for manufacturing an inductance element according to claim 6, further comprising the steps of:

S6c. Cover and protect the exposed wire of the magnet part with high temperature tape, or protect the exposed wire by dipping the mold release agent;

S7c, preheat the inductor to 130~160°C, and spray a layer of 0.02-0.1mm thick at least one of gray alkyd paint, epoxy paint, novolak, epoxy polyester phenolic paint on the surface of the inductor, after spraying Bake curing at 130~160℃.

9. The method for manufacturing an inductance element according to claim 6, further comprising the steps of:

S8c. Bend the two ends of the copper wire exposed outside the magnet, so that the two ends of the copper wire are attached to the surface of the magnet to form electrode pins, and the surface of the electrode pins is mechanically polished or laser etched to remove the nanocomposite surface of the copper wire. After insulation, the pins are tinned or tinned.

10. The method for manufacturing an inductance element according to claim 6, further comprising the steps of:

S8d, punching and bending the tin-plated copper sheet, prefabricating electrode pins, assembling the two ends of the copper wire exposed outside the magnet with the electrode pins, and welding the two ends of the copper wire to the electrode pins.

11. The manufacturing method of an inductance element according to claim 7, wherein in the step S2b, a plurality of limit wire grooves are arranged on the prefabricated base, and the corresponding number of copper wires processed in the step S2a are pressed according to the The designed direction is placed in the limit wire groove.

12. An inductance element, comprising a wire and a magnet, wherein both ends of the wire are exposed outside the magnet, wherein the magnet comprises iron-based magnetic powder particles, and the iron-based magnetic powder particles are coated with ferrous salt and dioxide The composite insulating layer of silicon, the inductive element can maintain performance at 500~960°C, preferably 700~900°C.

13 . The inductor element according to claim 12 , wherein the surface of the wire is covered with a nanocomposite insulating layer, and the nanocomposite insulating layer is uniformly distributed with nanometer oxides. 14 .

14 . The inductor element according to claim 13 , wherein the inductor element is covered with a layer of resin. 15 .

15. The inductance element according to claim 12-14, wherein a wire slot extending from one end of the magnet to the other end of the magnet is provided in the magnet, the wire is inserted in the wire slot, and the wire is inserted into the wire slot. The wire slots are exposed at both ends; the two ends of the wire are connected with electrode pins, and the top surface edges of both ends of the magnet are provided with wire grooves for accommodating the electrode pins, and the width of the wire grooves is equal to the width of the magnet; the electrode pins are formed by the wire The two ends of the wire exposed outside the magnet are formed by bending, the two ends of the wire are symmetrically attached to the surface of the magnet, and the width of the two ends of the wire is larger than that of the middle of the wire.

16. The inductance element according to claims 12-14, wherein a wire slot extending from one end of the magnet to the other end of the magnet is provided in the magnet, the wire is inserted in the wire slot, and the wire is inserted into the wire slot. The wire slots are exposed at both ends; electrode pins are connected to both ends of the wire, and the top surface edges of both ends of the magnet are provided with wire grooves for accommodating the electrode pins, and the width of the wire grooves is equal to the width of the magnet; the electrode pins are plated with The middle part of the tin wire is prefabricated by bending, and the first folding leg and the second folding leg are formed by bending; the first folding leg of the electrode pin is provided with a pin fixing groove, and the two ends of the wire can be inserted into the first folding leg of the electrode pin. In the pin fixing groove on the folding foot, the second folding foot of the electrode pin can be attached to the wire groove of the magnet by brazing or laser welding in the pin fixing groove; the width of the second folding foot is larger than that of the wire. width, and the width of the second folding leg is less than or equal to the width of the magnet.

17. The inductance element according to claim 15, 16, characterized in that, the magnet is composed of a prefabricated bottom blank and a top blank; the wire is placed on the prefabricated bottom blank, and both ends are exposed outside the prefabricated bottom blank; the prefabricated bottom blank The top surface of the blank is provided with a limit wire groove parallel to the length direction of the prefabricated bottom blank, the middle of the wire is placed in the limit wire groove, and the two sides of the wire are in contact with the two side walls of the limit wire groove; the prefabricated bottom blank can be connected to the top blank. Fit the compression wire.