CN107548174B - Ceramic heating element for automobile thermostat and preparation method thereof - Google Patents
Ceramic heating element for automobile thermostat and preparation method thereof Download PDFInfo
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- CN107548174B CN107548174B CN201710909683.6A CN201710909683A CN107548174B CN 107548174 B CN107548174 B CN 107548174B CN 201710909683 A CN201710909683 A CN 201710909683A CN 107548174 B CN107548174 B CN 107548174B
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- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
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- Resistance Heating (AREA)
Abstract
The invention discloses a ceramic heating element for an automobile thermostat and a preparation method thereof, the ceramic heating element comprises a heating element, the heating element comprises an outer insulating layer and an inner insulating layer, the outer insulating layer and the inner insulating layer are both made of alumina ceramic, a heating circuit is arranged between the outer insulating layer and the inner insulating layer, a through hole is formed in the inner insulating layer, a lead seat is arranged at the lower part of the heating element, a lead hole is formed in the lead seat, the through hole, the lead hole and the lead hole are connected by metal resistance paste, the heating element, the lead seat and the heating circuit are sintered together at high temperature to form a whole, at least two electrodes are connected to two ends of the heating circuit, and at least two leads penetrate through the lead holes and are respectively connected to the electrodes by the metal resistance paste. By adopting the structure, the ceramic heating element has the advantages of quick heating, good insulating property, stable heating performance, uniform heating temperature and the like, and can not cause the problems of resistance oxidation, power attenuation and the like; the preparation method of the ceramic heating element is simple and feasible, and the product percent of pass is high.
Description
Technical Field
The invention relates to the technical field of automobile thermostats, in particular to a ceramic heating element for an automobile thermostat and a preparation method thereof.
Background
A thermostat, also called a thermostat, is a valve for controlling a flow path of a cooling fluid, and is a thermostat, which generally includes a temperature sensing element for opening and closing a flow of air, gas or liquid by expanding or contracting.
With the increasing demands on fuel consumption and exhaust emissions of automobiles, the role and advantages of electronic thermostats in this respect are recognized, and the market demand for electronic thermostats is increasing. And the price of the electronic thermostat is more than 10 times higher than that of the ordinary thermostat, so customers need highly reliable electronic thermostat elements. For electronic thermostats the performance is mainly reflected on the sensor element. The sensor element consists of a body, a body cover, a sealing piece, a rubber tube, wax pellets, a push rod, a heating element and a sealing ring.
At present, a heating element is added in an inductor element in the existing electronic thermostat, and the existing heating element is generally manufactured by winding an electric heating wire 9 on a plastic 7 framework (as shown in fig. 12, a sealing ring 8 is further arranged outside the plastic 7), or by printing a resistor on a metal substrate and leading out a wire when the electronic thermostat is used, and then injection molding the electric heating element into a specific shape. The internal pressure of the inductor assembly can reach more than 25MPa when the inductor assembly works, but the plastic strength of the existing heating element is not high, and the metal substrate is conductive and easy to leak electricity, so that the reliability of the inductor is affected. The heating wire or the metal substrate heats for a long time and is exposed in paraffin, the insulating property is poor, in addition, the plastic skeleton has low strength under a high-temperature environment and is easy to deform, the sealing of the sealing ring is affected, the pressure of 25MPa cannot be born, the paraffin is leaked, and the reliability of the inductor is affected.
In order to solve the above problems, the Chinese patent with the publication number of CN 103002604B (publication day 2015.11.25) discloses a heating element for an electronic thermostat and a preparation method thereof, wherein the heating element is positioned in an inductor of the electronic thermostat and comprises a thermistor, a heating element head and a base, the heating element is made of ceramic material, the thermistor is embedded in the heating element head, one end of a wire is connected with the thermistor, and the other end of the wire penetrates out of the base. The heating element is prepared by the following method: (1) The alumina ceramic green body is prepared by the raw materials with the mass percentage of Al 2O3≥97％,SiO2≤1％,Fe2O3 less than or equal to 0.5 percent, caO less than or equal to 1 percent and other impurities less than or equal to 0.5 percent; (2) Embedding a thermistor and a lead into the alumina ceramic green body, and then performing compression molding; (3) Sintering the heating element in a reducing atmosphere, wherein the reducing atmosphere is mixed gas of 30% hydrogen and 70% nitrogen or 100% hydrogen. The invention has simple structure, low cost, good sealing effect and strong practicability. The invention improves the heating element of the metal matrix into the ceramic matrix, maintains good heat conduction performance, generates heat uniformly, has good insulating performance, avoids the possible electric leakage phenomenon of the heating element in practical application, and ensures that the performance of the electronic temperature regulator is more stable and reliable. Meanwhile, the ceramic heating element prepared by the method has high strength, can bear 50MPa pressure, is more reliable, has low cost and strong practicability.
However, the above patent has the following problems: 1. wire material and firing problems: the sintering temperature of ceramics with the alumina content of more than 97 is generally above 1500 ℃, and common materials such as nickel, copper and the like are melted when being used as leads; the wires are buried in the ceramic, and the ceramic is burnt to have about 15% shrinkage, but the wires are not, so that the ceramic is usually cracked; 2. thermistor material and firing problems: the thermistor is used for heating and is usually referred to as a PTC semiconductor thermistor, and the main component of the thermistor is barium titanate, and if the thermistor is buried in an alumina green body, the thermistor can have the problems of melting and cracking and reacting with alumina ceramics; 3. the connection of the lead wires to the thermistor is also inconvenient.
Disclosure of Invention
The invention aims to solve the technical problems of providing the ceramic heating element for the automobile thermostat and the preparation method thereof, wherein the ceramic heating element has the advantages of quick heating, good insulating property, stable heating performance, uniform heating temperature, quick heat transfer speed and high heat utilization rate, and the problems of resistance oxidation, power attenuation and the like do not occur; the preparation method of the ceramic heating element is simple and feasible, and the product percent of pass is high.
In order to solve the technical problems, the invention adopts the following technical scheme:
The utility model provides a ceramic heating element for automobile temperature regulator, includes the heat-generating body, the heat-generating body includes outer insulating layer and interior insulating layer, outer insulating layer and interior insulating layer are aluminium oxide pottery, and the heating circuit is arranged in between outer insulating layer and the interior insulating layer, it has the through-hole to open on the interior insulating layer, the lower part of heat-generating body is provided with the lead frame, it has the lead hole to open in the lead frame, in through-hole and the lead hole and all be connected with metal resistance thick liquids between the two, heat-generating body, lead frame and heating circuit three are through high temperature cofiring into a whole, the both ends of heating circuit are connected with two at least electrodes, and two piece at least lead wires pass the lead hole, and pass through metal resistance thick liquids are connected to respectively on the electrode.
Preferably, the lead is nickel wire or copper wire, the outer insulating layer and the inner insulating layer are both made of alumina ceramics with the mass percentage of 92-96.5%, and the material of the lead seat is the same as that of the heating element.
Preferably, the heating element is tubular, the lead seat comprises a lead seat head and a lead seat main body which are integrally formed, and the heating element is in interference fit with the lead seat head.
Preferably, the lead seat head is made into a cylindrical shape, the lead seat head is clamped in the heating body, and the inner diameter of the heating body is 0.14-0.20mm smaller than the outer diameter of the lead seat head.
Preferably, the lead seat head is made into a tube shape, the heating element is clamped in the lead seat head, and the outer diameter of the heating element is 0.14-0.20mm larger than the inner diameter of the lead seat head.
Preferably, the metal resistance paste is prepared from 65-100% by weight of tungsten powder or molybdenum powder and 0-35% by weight of porcelain powder, and the heating circuit is prepared from the metal resistance paste and is shaped like a Chinese character 'zhi'.
The preparation method of the ceramic heating element for the automobile thermostat comprises the following steps:
step 1, manufacturing metal resistor paste: rolling tungsten powder or molybdenum powder and porcelain powder into metal resistance slurry, and adding an adhesive, a solvent and a dispersing agent during rolling;
Step 2, manufacturing an outer insulating layer and an inner insulating layer: forming an outer insulating layer and an inner insulating layer from an alumina ceramic tape-cast green body, and punching a through hole in the inner insulating layer;
Step 3, printing a heating circuit: printing metal resistance paste on the outer side of the inner insulating layer by using a screen printing technology to form a heating circuit, wherein the through hole of the inner insulating layer is filled with the metal resistance paste, and an electrode is printed on the inner side of the inner insulating layer at a position corresponding to the through hole;
Step 4, manufacturing a heating body: coating a layer of adhesive on the outer surface of the inner insulating layer and the inner surface of the outer insulating layer, adhering the outer insulating layer on the outer side of the inner insulating layer, rolling the outer insulating layer and the inner insulating layer into a tube shape through a metal rod core to form a heating body, wherein the two electrodes are positioned on the same diameter, carrying out isostatic pressing molding on the heating body and the metal rod core, and then extracting the metal rod core from the heating body;
step 5, manufacturing a lead seat: forming a lead seat by hot die casting or injection molding by using alumina ceramic, and reserving a lead hole in the lead seat;
step 6, bisque firing and metallization: bisque firing the lead seat, and printing or coating metal resistor slurry in the lead hole and on the surface and the side surface after bisque firing;
step 7, aligning: the head of the lead seat is placed in the heating body, and when the head of the lead seat is placed in the heating body, the lead hole is aligned with the electrode, so that the lead hole and the electrode are positioned on the same diameter;
step 8, co-firing: under reducing gas, fixing the heating body, the lead seat and the heating circuit into a whole through a jig, and co-firing at high temperature, wherein the reducing gas comprises 35-75% of hydrogen and 25-65% of nitrogen by volume percent;
step 9, nickel plating: plating nickel in the lead hole;
Step 10, high-temperature brazing: soldering the lead hole and the lead at high temperature by using silver copper or pure silver solder or nickel soldering paste;
Step 11, glaze sealing: and sealing the lead seat and the heating body by glaze under the condition of no higher than the brazing temperature and reducing gas.
Preferably, in the step 4, a staggered lap joint is formed at the edge when the outer insulating layer and the inner insulating layer are bonded.
Preferably, in the step 6, the temperature of the bisque firing is 1100-1400 ℃; in the step 8, the cofiring temperature is 1550-1650 ℃; in the step 10, the brazing temperature is 700-1000 ℃; in the step 11, the glazing sealing temperature is 700-1000 ℃ and is not higher than the brazing temperature.
Preferably, in the step 8, before the reducing gas is introduced, the hydrogen and the nitrogen are passed through a wet hydrogen barrel, and water with a certain temperature is filled in the wet hydrogen barrel, and the water temperature is 38-45 ℃.
Compared with the prior art, the invention has the beneficial effects that:
1. The invention adopts alumina ceramics to wrap the heating circuit formed by the printed metal resistance slurry inside, and the heating circuit is used as a heating body by cofiring, and has the advantages of good insulating property, high strength, quick heat conduction, uniform heating, high power density, high safety performance and long service life, and can realize quick temperature rise and temperature compensation.
2. In the prior art, a metal substrate or an electric heating wire is generally in direct contact with wax, the insulation is poor, the power density is not as high as that of a ceramic heating element, and the plastic framework is easy to deform at high temperature and has poor quality. In the invention, the heating circuit is arranged between the outer insulating layer and the inner insulating layer, and the three layers are sintered together at high temperature to form a whole, so that high-temperature deformation is avoided.
3. Compared with the Chinese patent with the publication number of CN 103002604B, in the heating element, the thermistor and the lead are buried in the ceramic and are co-fired, so that the method is not easy to realize in actual operation, and in the invention, the mode of co-firing the outer insulating layer, the heating circuit and the inner insulating layer into a whole is easy to realize.
4. The heating element has uniform heating temperature, and the temperature difference is small under the same voltage, so that the performance of the temperature regulator can be improved, the temperature of an engine can be effectively controlled, the abrasion of the engine is reduced, and the fuel economy is improved.
5. The invention has simple structure, more convenient installation than other heating bodies during use, simple operation and high working efficiency.
6. In the preparation method, the heating circuit is printed on the inner insulating layer, and the operation is simple and convenient.
7. In the preparation method of the invention, the heating body, the lead seat and the heating circuit are co-fired, and then the lead Kong Dunie is soldered with the lead at high temperature, so that the lead is not melted due to co-firing with ceramic.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are required in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only preferred embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a perspective view of the present invention;
FIG. 2 is a left side view of the present invention;
FIG. 3 is a bottom view of the present invention;
FIG. 4 is a cross-sectional view taken along line A-A of FIG. 3;
Fig. 5 is a schematic structural view of the inner insulating layer outer side 121 and the heat generating circuit 4 in the present invention;
FIG. 6 is a schematic view of the inner side 122 of the inner insulating layer according to the present invention;
Fig. 7 is a perspective view of the lead frame 2 according to the present invention;
fig. 8 is a front view of the lead frame 2 according to the present invention;
Fig. 9 is a top view of the lead frame 2 according to the present invention;
FIG. 10 is a cross-sectional view taken along line B-B of FIG. 9;
Fig. 11 is a cross-sectional view showing another structure of the lead frame 2 according to the present invention;
FIG. 12 shows a prior art heating element with a plastic 7 skeleton around an electric heating wire 9;
Fig. 13 is an assembled view of a heating element of the prior art.
In the figure, a 1-heating element, a 11-outer insulating layer, a 12-inner insulating layer, a 121-outer side of the inner insulating layer, a 122-inner side of the inner insulating layer, a 123-through hole, a 2-lead seat, a 21-lead seat head, a 22-lead seat main body, a 23-lead hole, a 3-lead, a 4-heating circuit, a 41-electrode, a 5-metal resistance paste, a 6-glaze, 7-plastic, an 8-sealing ring, a 9-heating wire and a 10-copper sleeve.
Detailed Description
The following describes the embodiments of the present invention further with reference to the drawings. The description of these embodiments is provided to assist understanding of the present invention, but is not intended to limit the present invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
As shown in fig. 1-4, the ceramic heating element for a temperature regulator disclosed by the invention comprises a heating element 1, wherein the heating element 1 comprises an outer insulating layer 11 and an inner insulating layer 12, the outer insulating layer 11 and the inner insulating layer 12 are both made of alumina ceramic, a heating circuit 4 is arranged between the outer insulating layer 11 and the inner insulating layer 12, a through hole 123 is formed in the inner insulating layer 12, a lead seat 2 is arranged at the lower part of the heating element 1, a lead hole 23 is formed in the lead seat 2, the through hole 123 and the lead hole 23 are connected by using metal resistance paste 5, so that the heating element 1, the lead seat 2 and the heating circuit 4 can be connected in a conducting manner, the heating element 1, the lead seat 2 and the heating circuit 4 are sintered together at high temperature to form a whole, two ends (the other end of the heating circuit 4 in fig. 5 is not unfolded) of the heating circuit 4 are connected with at least two electrodes 41, at least two leads 3 penetrate through the lead holes 23 and are respectively connected to the electrodes 41 by using the metal resistance paste 5, and the leads 3 are nickel wires or copper wires.
The outer insulating layer 11 and the inner insulating layer 12 are both alumina ceramics with the mass percentage of 92-96.5%. Meanwhile, in order to facilitate the manufacture of the invention, the material of the lead seat 2 is preferably the same as that of the heating element 1.
The heating element 1 is tubular, so that when the heating element 1 heats paraffin, the inner wall and the outer wall of the heating element 1 can heat paraffin, and the heating efficiency is greatly improved.
Referring to fig. 7 to 11, the lead frame 2 includes a lead frame head 21 and a lead frame body 22 integrally formed, and an interference fit between the heating body 1 and the lead frame head 21 allows the heating body 1 and the lead frame 2 to be combined more tightly, avoiding leakage of liquid when the ceramic heating element is used in a thermostat. As an example, as shown in fig. 7 to 10, the lead frame head 21 may be made cylindrical, and the lead frame head 21 is caught in the heat generating body 1, and at this time, the inner diameter D1 of the heat generating body 1 is smaller than the outer diameter D2 of the lead frame head 21 by 0.14 to 0.20mm. As a second embodiment, as shown in fig. 11, the lead frame head 21 may be formed in a tubular shape, and the heating element 1 is caught in the lead frame head 21, and the outer diameter D1 of the heating element 1 is 0.14 to 0.20mm larger than the inner diameter D2 of the lead frame head 21. Of course, the connection method between the lead holder 2 and the heating element 1 is not limited to the above two, and both may be clamped.
The metal resistance slurry 5 is prepared from high-temperature resistant metals such as tungsten powder (W) or molybdenum powder (Mo) and porcelain powder, wherein the mass percent of the tungsten powder or the molybdenum powder is 65-100%, the mass percent of the porcelain powder is 0-35%, the larger the specific gravity of the porcelain powder is, the larger the resistance of the metal resistance slurry 5 is, and the ratio of the tungsten powder or the molybdenum powder to the porcelain powder can be determined according to the requirements of products.
The heating circuit 4 is made of metal resistance paste 5, and the shape of the heating circuit is zigzag, as shown in fig. 5, so that the heating circuit 4 can be more uniformly and more distributed in the heating body 1, and the heating of the heating body 1 is faster and more uniform.
The invention also discloses a preparation method of the ceramic heating element for the automobile thermostat, which comprises the following steps:
step1, manufacturing metal resistance slurry 5: rolling tungsten powder or molybdenum powder and porcelain powder into metal resistance slurry 5, and adding an adhesive, a solvent and a dispersing agent during rolling;
step2, manufacturing an outer insulating layer 11 and an inner insulating layer 12: forming an outer insulating layer 11 and an inner insulating layer 12 from a green casting of alumina ceramic, and punching a through hole 123 in the inner insulating layer 12;
step 3, printing a heating circuit 4: printing metal resistance paste 5 on the outer side 121 of the inner insulating layer by using a screen printing technology to form a heating circuit 4, wherein the through hole 123 of the inner insulating layer 12 is filled with the metal resistance paste 5 as shown in fig. 5, and printing an electrode 41 on the inner side 122 of the inner insulating layer at a position corresponding to the through hole 123 as shown in fig. 6;
Step 4, manufacturing a heating element 1: the outer surface of the inner insulating layer 12 and the inner surface of the outer insulating layer 11 are coated with an adhesive, the outer insulating layer 11 is adhered to the outer side 121 of the inner insulating layer, and the outer insulating layer 11 and the inner insulating layer 12 are rolled into a tube shape by a metal rod core to form the heating element 1, and the two electrodes 41 are located on the same diameter. In addition, in order to smoothly roll the outer insulating layer 11 and the inner insulating layer 12 into a tube shape, the two layers form staggered lap joints at the edge when being bonded; the heating body 1 and the metal rod core are molded by isostatic pressing, and then the metal rod core is extracted from the heating body 1;
Step 5, manufacturing a lead seat 2: forming a lead seat 2 by hot die casting or injection molding by using alumina ceramic, and reserving a lead hole 23 in the lead seat 2;
Step 6, bisque firing and metallization: the lead seat 2 is subjected to biscuit firing, and the alumina ceramic is densified due to the high-temperature sintering of the alumina ceramic, so that the lead seat 2 is contracted, the heating element 1 and the lead seat head 21 which are in interference fit originally can be smoothly placed in the heating element 1 after the biscuit firing of the lead seat 2, meanwhile, the lead seat 2 can have certain strength after biscuit firing, and the following steps are also performed on the basis of the first embodiment, aiming at the condition that the lead seat head 21 is clamped in the heating element 1 in the first embodiment. If the heating element 1 is caught in the lead frame head 21 in the second embodiment, the heating element 1 is bisque-fired, and after the bisque-firing shrinkage of the heating element 1, the heating element 1 can be smoothly put into the lead frame head 21. The temperature of the bisque firing is 1100-1400 ℃. After the biscuit firing, the metal resistance paste 5 is printed or coated on the inner surface and the side surface of the lead hole 23, namely the part contacted with the heating element 1, so that the lead hole 23 is metallized, namely the lead hole 23 can conduct electricity, and the purpose of the metallization is to lead the lead hole 23 and the through hole 123 to be connected together in a conducting way;
step 7, aligning: the lead seat head 21 is put into the heating element 1, and when the lead seat head is put into the heating element 1, the lead hole 23 is aligned with the electrode 41, so that the lead hole and the electrode are positioned on the same diameter;
Step 8, co-firing: under reducing gas, the three parts of the heating body 1, the lead seat 2 and the heating circuit 4 are fixed by a jig and are sintered together at high temperature to form a whole, wherein the reducing gas comprises 35-75% of hydrogen and 25-65% of nitrogen by volume percent, and the temperature of the cofiring is 1550-1650 ℃. Because the lead seat 2 is subjected to biscuit firing before, the shrinkage of the lead seat 2 is smaller during cofiring, the shrinkage of the heating body 1 is larger, the shrinkage ratio of the two is inconsistent, and after cofiring, the heating body 1 can clamp the lead seat 2, so that the two form interference fit.
In the co-firing process, because carbon impurities are contained in the alumina ceramic, the carbon impurities can directly influence the sintering quality, so that before reducing gas is introduced, hydrogen and nitrogen can pass through a wet hydrogen barrel, water with a certain temperature is filled in the wet hydrogen barrel, the water temperature is 38-45 ℃, so that the hydrogen and the nitrogen carry certain water vapor into a sintering furnace, and at a high temperature, water molecules have certain oxidation characteristics, and carbon monoxide or carbon dioxide is generated with the carbon impurities and discharged, so that the carbon impurities of the alumina ceramic are effectively removed, and the sintering quality is ensured;
Step 9, nickel plating: nickel plating in the lead hole 23;
step 10, high-temperature brazing: the lead hole 23 and the lead 3 are brazed at a high temperature by silver copper or pure silver solder or nickel soldering paste, the brazing temperature is 700-1000 ℃, and at the moment, the lead hole 23 is completely sealed by the silver copper or pure silver solder or nickel soldering paste, so that the leakage phenomenon is avoided;
Step 11, glaze sealing: the lead seat 2 and the heating body 1 are sealed by the glaze 6 under the conditions of no higher than the brazing temperature and the reducing gas, namely the temperature is 700 ℃ to 1000 ℃ and no higher than the brazing temperature, so that the paraffin is prevented from leaking when the invention is used. As the glaze 6 is an inorganic material, compared with other organic sealing materials, the product has good sealing performance and is not easy to age.
The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, and yet fall within the scope of the invention.
Claims (4)
1. A preparation method of a ceramic heating element for an automobile thermostat is characterized by comprising the following steps: the ceramic heating element comprises a heating body, the heating body comprises an outer insulating layer and an inner insulating layer, the outer insulating layer and the inner insulating layer are both alumina ceramic, a heating circuit is arranged between the outer insulating layer and the inner insulating layer, a through hole is formed in the inner insulating layer, a lead seat is arranged at the lower part of the heating body, a lead hole is formed in the lead seat, the through hole, the lead hole and the lead hole are connected through metal resistance slurry, the heating body, the lead seat and the heating circuit are all sintered together at high temperature to form a whole, two ends of the heating circuit are connected with at least two electrodes, and at least two leads penetrate through the lead hole and are respectively connected to the electrodes through the metal resistance slurry;
the preparation method comprises the following steps:
step 1, manufacturing metal resistor paste: rolling tungsten powder or molybdenum powder and porcelain powder into metal resistance slurry, and adding an adhesive, a solvent and a dispersing agent during rolling;
Step 2, manufacturing an outer insulating layer and an inner insulating layer: forming an outer insulating layer and an inner insulating layer from an alumina ceramic tape-cast green body, and punching a through hole in the inner insulating layer;
Step 3, printing a heating circuit: printing metal resistance paste on the outer side of the inner insulating layer by using a screen printing technology to form a heating circuit, wherein the through hole of the inner insulating layer is filled with the metal resistance paste, and an electrode is printed on the inner side of the inner insulating layer at a position corresponding to the through hole;
Step 4, manufacturing a heating body: coating a layer of adhesive on the outer surface of the inner insulating layer and the inner surface of the outer insulating layer, adhering the outer insulating layer on the outer side of the inner insulating layer, rolling the outer insulating layer and the inner insulating layer into a tube shape through a metal rod core to form a heating body, wherein the two electrodes are positioned on the same diameter, carrying out isostatic pressing molding on the heating body and the metal rod core, and then extracting the metal rod core from the heating body;
step 5, manufacturing a lead seat: forming a lead seat by hot die casting or injection molding by using alumina ceramic, and reserving a lead hole in the lead seat;
step 6, bisque firing and metallization: bisque firing the lead seat, and printing or coating metal resistor slurry in the lead hole and on the surface and the side surface after bisque firing;
step 7, aligning: the head of the lead seat is placed in the heating body, and when the head of the lead seat is placed in the heating body, the lead hole is aligned with the electrode, so that the lead hole and the electrode are positioned on the same diameter;
step 8, co-firing: under reducing gas, fixing the heating body, the lead seat and the heating circuit into a whole through a jig, and co-firing at high temperature, wherein the reducing gas comprises 35-75% of hydrogen and 25-65% of nitrogen by volume percent;
step 9, nickel plating: plating nickel in the lead hole;
Step 10, high-temperature brazing: soldering the lead hole and the lead at high temperature by using silver copper or pure silver solder or nickel soldering paste;
Step 11, glaze sealing: and sealing the lead seat and the heating body by glaze under the condition of no higher than the brazing temperature and reducing gas.
2. The method for manufacturing a ceramic heating element for a thermostat of a vehicle according to claim 1, characterized in that: in the step 4, dislocation lap joints are formed at the edges when the outer insulating layer and the inner insulating layer are bonded.
3. The method for manufacturing a ceramic heating element for a thermostat of a vehicle according to claim 1, characterized in that: in the step 6, the temperature of the bisque firing is 1100-1400 ℃; in the step 8, the cofiring temperature is 1550-1650 ℃; in the step 10, the brazing temperature is 700-1000 ℃; in the step 11, the glazing sealing temperature is 700-1000 ℃ and is not higher than the brazing temperature.
4. The method for manufacturing a ceramic heating element for a thermostat of a vehicle according to claim 1, characterized in that: in the step 8, before the reducing gas is introduced, hydrogen and nitrogen are led to pass through a wet hydrogen barrel, and water with a certain temperature is filled in the wet hydrogen barrel, and the water temperature is 38-45 ℃.
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| CN108503391A (en) * | 2018-04-10 | 2018-09-07 | 珠海惠友电子有限公司 | A kind of manufacturing process of ceramic heating part |
| CN108617040B (en) * | 2018-06-06 | 2021-02-02 | 南平市弘毅电子科技有限公司 | Ceramic heating rod with ceramic core electrode lead and manufacturing method thereof |
| CN108817598B (en) * | 2018-08-01 | 2024-05-31 | 无锡康伟工程陶瓷有限公司 | Magnetron cathode antenna brazing assembly |
| CN111842727B (en) * | 2020-07-13 | 2022-08-02 | Oppo（重庆）智能科技有限公司 | Jig for wire installation |
| CN113179559A (en) * | 2020-12-01 | 2021-07-27 | 深圳市卓力能技术有限公司 | Heating body and preparation method thereof, heating assembly and aerosol generating device |
| CN113698224B (en) * | 2021-07-22 | 2023-03-03 | 中广核研究院有限公司 | Resistance welding connection device and silicon carbide connection method |
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| CN207321567U (en) * | 2017-09-29 | 2018-05-04 | 珠海惠友电子有限公司 | A kind of vehicle thermoregulator ceramic heating element |
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| CN1649449A (en) * | 2004-01-20 | 2005-08-03 | 珠海粤科清华电子陶瓷有限公司 | High temperature coburning heating element and its producing method |
| CN207321567U (en) * | 2017-09-29 | 2018-05-04 | 珠海惠友电子有限公司 | A kind of vehicle thermoregulator ceramic heating element |
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