CN206635411U - Wire-drawing die with a variety of coatings - Google Patents

Abstract

The utility model provides a wire drawing die with various coatings, comprising a wire drawing die substrate, and a silicon carbide layer, a silicon carbide-diamond gradient composite coating, a diamond coating and the like which are sequentially arranged on the wire drawing die substrate Diamond coating, in the silicon carbide-diamond gradient composite coating, along the thickness direction from the silicon carbide layer to the diamond coating, the content of silicon carbide gradually decreases while the content of diamond gradually increases. The silicon carbide layer and silicon carbide-diamond gradient composite coating can effectively weaken the thermal expansion difference between the substrate and the diamond coating, improve the bonding strength of the diamond coating, and the diamond-like layer on the diamond coating can reduce the roughness of the diamond coating , to avoid the sharp edges and corners of diamond grains causing stress concentration during processing. Such a multi-layer structure on the wire drawing die can effectively improve the service life of the wire drawing die.

Description

Drawing dies with various coatings

technical field

The utility model relates to the technical field of diamond coating preparation, in particular to a wire drawing die with multiple coatings.

Background technique

Drawing dies are gradually unable to meet market demand due to their sticky materials, easy wear of working parts, dimensional tolerances that cannot be kept stable for a long time, short service life, and low production efficiency. The best way to solve the above problems is to deposit a protective coating with high hardness and high wear resistance on the surface of the wire drawing die. Due to its high hardness, good wear resistance, impact resistance, chemical stability and other properties, diamond coating is the best choice for the surface protection coating of wire drawing dies. At present, hot wire vapor deposition (HFCVD) is usually used to deposit a certain thickness of micro/nano diamond coating on the surface of the wire drawing die as a surface protection layer, thereby prolonging the service life of the die.

Due to the different thermal expansion coefficients between the diamond coating and the wire drawing die substrate, the bonding strength between the diamond coating deposited by HFCVD and the substrate is poor, and peeling is prone to occur under high impact force. In addition, the surface of the obtained diamond coating is relatively rough, so that when the wire drawing die is used to draw the wire or pipe, a product with a relatively high surface roughness is obtained. Therefore, it is generally necessary to polish the diamond coating, such as magnetic grinding and polishing, Laser polishing, thermochemical polishing, ion beam polishing, etc. The above polishing techniques are not only cumbersome and difficult to operate, but also the force applied during the polishing process will cause great residual stress, which will cause certain damage to the service life of the coating.

Utility model content

In view of this, the utility model provides a wire drawing die with multiple coatings, which deposits a silicon carbide layer, a silicon carbide-diamond gradient composite coating, a diamond coating and a diamond-like coating sequentially on the wire drawing die substrate, It is used to solve the problem of insufficient adhesion between the existing diamond coating and the base of the wire drawing die and the relatively large roughness of the diamond coating, thereby improving the service life and processing quality of the wire drawing die and reducing the polishing process.

Specifically, in the first aspect, the present application provides a wire drawing die with various coatings, including a wire drawing die base, and a silicon carbide layer and a silicon carbide-diamond gradient composite coating sequentially arranged on the wire drawing die base , a diamond coating and a diamond-like coating, in the silicon carbide-diamond gradient composite coating, along the thickness direction from the silicon carbide layer to the diamond coating, the silicon carbide content gradually decreases while the diamond content gradually increases.

The presence of the silicon carbide layer can hinder the diffusion of cobalt in the matrix to the diamond coating, and form a small amount of cobalt silicon compound with cobalt, eliminating the role of cobalt in catalyzing the formation of graphite.

In the silicon carbide-diamond gradient composite coating, the composition, hardness and thermal expansion coefficient are distributed in gradients, and there is no new interface and interface with sudden composition change, so the thermal stress of the film can be reduced to zero, and the film thickness of the diamond coating can be improved. base bonding strength; and the silicon carbide in it can enhance the toughness of the coating. The silicon carbide-diamond gradient composite coating can further block the diffusion of cobalt metal.

A layer of diamond-like coating deposited on the diamond coating. Due to its extremely low friction coefficient and excellent wear resistance, the diamond-like coating can be used as a lubricating layer, which greatly reduces the roughness of the diamond coating surface and reduces the wear resistance of the diamond coating. The stress concentration of the grain edges and corners in the coating reduces the subsequent polishing process of the diamond coating, avoids the great residual stress caused by the force applied during the polishing process, and prolongs the effective service life of the coating. Improve the service life and processing quality of the wire drawing die.

In the present application, the thickness of the diamond-like coating is 2-6 microns. More preferably 4-6 microns.

In the present application, the silicon carbide layer has a thickness of 0.5-2 microns, preferably 0.8-2 microns. The silicon carbide grain size in the silicon carbide layer is at the nanometer level (ie, within 100 nanometers), specifically, it may be 30-80 nanometers. Appropriate thickness can ensure that the silicon carbide layer can be well attached to the surface of the substrate, and provide a good foundation for the subsequent deposition of silicon carbide-diamond gradient composite coating and diamond coating, and can effectively prevent the cobalt in the substrate from diffusing to the diamond coating .

In the present application, the thickness of the silicon carbide-diamond gradient composite coating is 2-5 microns. Appropriate gradient composite coating thickness is conducive to the formation of a good intermediate transition layer, so that the elastic modulus and thermal expansion coefficient of the coating change uniformly between the elastic modulus and thermal expansion coefficient of the substrate and the diamond coating, thereby reducing The peak shear stress of the diamond coating improves the adhesion of the diamond coating to the substrate.

In the silicon carbide-diamond gradient composite coating, the silicon carbide grain size is at the nanometer level, specifically 30-80 nanometers; the diamond grain size is at the nanometer level or micron level (for example, 1-2 microns), specifically it can be It is 20-50 nanometers, 1.5-2 microns.

In the present application, the thickness of the diamond coating is 2-8 microns. The diamond grains of the diamond coating are at the nanometer or micrometer level, specifically 20-50 nanometers, 1.5-2 micrometers. Among them, when the diamond grains in the coating are at the micron level, the hardness and strength of the coating will be higher, but the roughness of the diamond coating will increase accordingly. Preferably, the diamond grains of the diamond coating are nanoscale.

In the present application, along the thickness direction of the silicon carbide-diamond gradient composite coating, the content of silicon carbide and diamond varies between greater than 0 and less than 100%, so that from the silicon carbide layer to the diamond coating, the content of silicon carbide is changed from 100% to 100%. % to 0 gradually decreases, while the diamond content gradually increases from 0 to 100%, that is, the entire coating on the surface of the substrate from the substrate to the top layer, the silicon carbide content gradually decreases from 100% to 0, while the diamond content gradually increases from 0 to 100%, No new interface is added.

In the present application, in the entire silicon carbide-diamond gradient composite coating, the volume fraction of silicon carbide may be 30-70%, such as 40%, 50%, or 60%. A large relative content of silicon carbide can enhance the adhesion and fracture toughness of the film; a small relative content will result in higher hardness and strength of the coating.

In the present application, in order to make the diamond coating obtain better adhesion, the thickness of the diamond coating is preferably no more than 4 times the thickness of the silicon carbide-diamond gradient composite coating, for example, it can be 1-3 times or 1-2 times the thickness of the silicon carbide-diamond gradient composite coating.

In the present application, the material of the wire drawing die base is cemented carbide, alloy steel or ceramics. Wherein, the cemented carbide may be tungsten-cobalt cemented carbide (WC-Co) or tungsten-titanium-cobalt cemented carbide (the components are tungsten carbide, titanium carbide and cobalt).

The present application has a wire drawing die with multiple coatings, by first setting a silicon carbide layer and a silicon carbide-diamond gradient composite coating as a thermal expansion coefficient transition layer and metal cobalt (Co) on the cemented carbide substrate before depositing the diamond coating. The barrier layer can effectively reduce the thermal stress in the diamond film, effectively improve the bonding strength of the diamond coating, and set the diamond-like coating on the diamond coating as a lubricating layer, which greatly reduces the surface roughness of the diamond coating and reduces the diamond grain size. The stress concentration of grain edges and corners during work.

Correspondingly, the second aspect of the present application provides a method for preparing a wire drawing die with multiple coatings, comprising the following steps:

Taking the wire drawing die substrate and pretreating it; the pretreatment includes sandblasting the workpiece substrate, followed by ultrasonic cleaning with acetone and ethanol;

A silicon carbide layer, a silicon carbide-diamond gradient composite coating and a diamond coating are successively applied on the pretreated wire drawing die substrate by means of hot wire vapor deposition, wherein the silicon carbide-diamond gradient composite coating is made , the silicon carbide content gradually decreases along the thickness growth direction while the diamond content gradually increases;

A diamond-like coating is deposited on the wire drawing die deposited with the diamond coating, and finally a wire drawing die with various coatings is obtained.

Wherein, before the deposition and growth of the diamond-like coating, it also includes: first adopting acetone and ethanol to ultrasonically clean the wire drawing die deposited with the diamond coating, and then cleaning the ion source, wherein: the conditions for cleaning the ion source for:

Place the wire drawing die in the reaction chamber, draw the vacuum of the reaction chamber below 3×10 ^-3 Pa, and heat it to 140-160°C; The vacuum degree of the reaction chamber is maintained at 01.-0.5Pa, the ion source is turned on, the base bias voltage is adjusted to -800--1200V, and the cleaning time of the ion source is 10-30 minutes.

In one embodiment of the present application, the method of depositing the diamond-like coating is magnetron sputtering, including:

Control the vacuum degree of the reaction chamber of the magnetron sputtering equipment to be (1-5)×10 ^-2 Pa, the temperature is 320-360°C, the current of the ion source is 6.5-12A, graphite is used as the target material, and the control of the The target power of the target is 1.9-7.2kW, the substrate negative bias is -300--600V, and the deposition time is 2-6h.

In the present application, a silicon carbide layer, a silicon carbide-diamond gradient composite coating and a diamond coating are sequentially deposited on the pretreated wire drawing die substrate, specifically including:

Using hot wire chemical vapor deposition equipment, using hydrogen and organosilane as reaction gases, depositing a silicon carbide layer on the surface of the pretreated wire drawing die substrate, controlling the organosilane to account for 0.01% to 1% of the total gas volume;

Then feed methane into the hot wire chemical vapor deposition equipment, that is, use hydrogen, methane and organosilane as reaction gases, control methane to account for 0.4% to 6% of the total gas volume, and organosilane to account for 0.01% to 1% of the total gas volume. %, deposited on the surface of the silicon carbide layer to form a silicon carbide-diamond gradient composite coating, gradually increase the methane flow during the reaction process, and gradually reduce the organosilane flow, so that the silicon carbide-diamond gradient composite coating In , the silicon carbide content gradually decreases along the thickness growth direction while the diamond content gradually increases;

When the organosilane flow rate is reduced to zero, methane is controlled to account for 0.4% to 6% of the total gas volume, and hydrogen and methane are used as reaction gases to deposit a diamond coating on the silicon carbide-diamond gradient composite coating; finally Get drawing dies with multiple coatings;

During the above deposition process, the vacuum chamber pressure is 0.5-10kPa, the filament temperature is 1500-2800°C, and the substrate temperature is 600-900°C.

In the present application, the organosilane includes one or more of tetramethylsilane, monosilane, disilane, monomethylsilane, and dimethylsilane.

In this application, when depositing silicon carbide-diamond gradient composite coating or diamond coating, the carbonization of diamond grains with different particle sizes can be obtained by controlling the content of reaction gas, vacuum chamber pressure, filament and substrate temperature, etc. Silicon-diamond gradient composite coating.

For example, when depositing a diamond coating, control methane to account for 0.6% to 2% of the total gas volume, the vacuum chamber pressure range is 2.5 to 6kPa, the filament temperature range is 1800 to 2800°C, the substrate temperature is 700 to 1000°C, and the deposition time For 1-6 hours, micron-sized diamond crystal grains are formed in the diamond coating. If the range of methane in the total gas volume is controlled to be 3% to 6%, the vacuum chamber pressure range is 0.5 to 2.5kPa, the filament temperature range is 1400 to 2200°C, the substrate temperature range is 500 to 700°C, and the deposition time is 3 to 11 hours , so that nano-scale diamond grains are formed in the diamond coating.

In the present application, the deposition time of each layer can be specifically set according to the thickness of the specific required deposition. Optionally, the deposition time for depositing the silicon carbide layer is 0.5 to 2 hours, and the deposition time for depositing the silicon carbide-diamond gradient composite coating is 2-6 hours, the deposition time for depositing the diamond coating is 1-11 hours, and the deposition time for depositing the diamond-like coating is 2-6 hours. Optionally, the thickness of the silicon carbide layer is 0.5-2 microns; the thickness of the silicon carbide-diamond gradient composite coating is 2-5 microns; the thickness of the diamond coating is 2-8 microns; the The thickness of the diamond-like coating is 2-6 microns.

The preparation method of the wire drawing die with multiple coatings provided by this application, sequentially deposits a silicon carbide layer, a silicon carbide-diamond gradient composite coating, a diamond coating and a diamond-like coating on the wire drawing die substrate, and can use the silicon carbide layer , Silicon carbide-diamond gradient composite coating effectively weakens the thermal expansion difference between the wire drawing die substrate and the diamond coating, reduces thermal stress, and improves the bonding strength of the diamond coating; at the same time, the diamond-like layer deposited on the diamond coating can reduce the diamond The roughness of the coating prevents the sharp edges and corners of the diamond grains from causing stress concentration during processing, which eventually leads to the shedding of the film and the failure of the drawing die. Such a multi-layer structure on the wire drawing die can effectively improve the service life of the wire drawing die, and also eliminates the need for subsequent polishing of the diamond coating, reducing production costs.

Description of drawings

Fig. 1 is the schematic cross-sectional structure diagram of the wire drawing die with multiple coatings in the embodiment of the present application; among the figure, 101 is the wire drawing die substrate, 102 is the silicon carbide layer, 103 is the silicon carbide-diamond gradient composite coating, and 104 is the diamond coating, 105 is a diamond-like coating.

detailed description

The following description is a preferred implementation of the embodiment of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the embodiment of the present application, some improvements and modifications can also be made. These improvements and retouching are also regarded as the scope of protection of the embodiments of the present application.

Example 1

A method for preparing a wire drawing die with multiple coatings, comprising the following steps:

(1) The YG8 (WC-8% Co) cemented carbide wire drawing die sold in the domestic market is used as the substrate, and the substrate is first subjected to wet sandblasting of white corundum. The pressure during sandblasting is 350kPa, and the sand particle size is 600 mesh. . The cemented carbide was then ultrasonically cleaned in acetone and alcohol for 20 minutes, and dried.

(2) The silicon carbide intermediate layer is prepared by the hot wire chemical vapor deposition method, and the silicon carbide layer is deposited on the surface of the pretreated cemented carbide substrate with hydrogen and tetramethylsilane as the reaction gas. The deposition conditions are as follows: organosilane gas The flow rate is 4sccm, the flow rate of hydrogen gas is 800sccm, the air pressure in the vacuum chamber is 3kPa, the distance between the filament and the sample is 9.5mm, the distance between the filament and the filament is 8mm, the temperature of the filament is 2200°C, the temperature of the substrate is 850°C, and the deposition time is 1 Hours, a silicon carbide (SiC) layer with a thickness of 1 micron is formed on the pretreated surface, and the silicon carbide grain size is 50-60 nanometers.

(3) Then feed methane gas and gradually reduce the flow of tetramethylsilane, keep the flow of hydrogen constant, at this time, prepare silicon carbide-diamond gradient composite coating with methane, tetramethylsilane and hydrogen as reaction gases, the specific The conditions are as follows: the methane gas flow rate initially introduced is 32 sccm, the tetramethylsilane gas flow rate is 4 sccm, the vacuum chamber pressure is reduced to 2 kPa, the distance between the filament and the sample is 8.5 mm, the distance between the filament and the filament is 8 mm, and the temperature of the filament is 2000°C , the substrate temperature is 680°C. In the preparation process, the gas flow rate of tetramethylsilane is gradually reduced until it approaches zero, and the total deposition time is 2 hours to obtain a silicon carbide-diamond gradient composite coating with a thickness of 2 microns; the silicon carbide-diamond gradient composite coating Among them, the silicon carbide grain is 30nm, the diamond grain is 40nm, the silicon carbide content gradually decreases along the thickness growth direction, and the diamond content gradually increases;

(4) Reduce the tetramethylsilane flow rate to zero, and continue to deposit nano-diamond coatings on the gradient composite coating with hydrogen and methane as reaction gases. The deposition conditions are as follows: the distance between the filament and the sample is 10 mm, and the distance between the filament and the filament The spacing is 8 mm; the flow rate of methane gas is 16sccm, the flow rate of hydrogen gas is 800sccm, and the volume ratio of methane to hydrogen is kept at about 2%; the pressure range of the vacuum chamber is 4kPa; the temperature range of the filament is 2400°C, and the temperature range of the substrate is 850°C; The time is 3.5 hours. The thickness of the obtained diamond film is about 4.5 microns, and the grain size is 1.5 microns;

(5) A layer of diamond-like coating was prepared on the diamond coating by using physical vapor deposition method with graphite target as the carbon source. The specific deposition conditions are as follows: first, clean the ion source and keep the background vacuum of the reaction chamber at 3× 10 ^-3 Pa, heat the temperature to 150°C, turn on the ion source, fill the reaction chamber with argon (Ar), adjust the input gas flow rate, and keep the vacuum degree of the reaction chamber at 5×10 ^-1 Pa, bias -800V, continuous 30 minutes. Then carry out diamond-like coating deposition, keep vacuum at 5×10 ^-2 Pa, temperature at 350°C, adjust deposition bias to -500V, ion current at 8A, target power at 4kW, and deposition time at 4 hours. Diamond-like carbon coating with a thickness of 4 microns;

After cooling with the furnace, the drawing die is taken out, and the drawing die with silicon carbide (SiC)-silicon carbide-diamond gradient composite coating-diamond-diamond-like carbon (DLC) coating is obtained. The schematic diagram of its structure is shown in Figure 1. Among them, 101 is the drawing die substrate, 102 is the silicon carbide layer, 103 is the silicon carbide-diamond gradient composite coating, 104 is the diamond coating, 105 is the diamond-like coating, 102, 103, 104, 105 are stacked on top of 101 in sequence. superior.

Example 2

A method for preparing a wire drawing die with multiple coatings, comprising the following steps:

(1) The YG6X (WC-6wt.% Co) hard alloy wire drawing die sold in the domestic market is used as the substrate, and the substrate is first subjected to wet sandblasting of white corundum. The pressure during sandblasting is 200kPa, and the sand particle size is 300 mesh; then ultrasonically clean the cemented carbide in acetone and alcohol for 15 minutes, and dry.

(2) adopt hot wire chemical vapor deposition method to deposit silicon carbide layer on the cemented carbide substrate surface after pretreatment, and its deposition condition is as follows: be reaction gas with hydrogen and dimethylsilane, the flow rate of dimethylsilane is 4sccm, The flow rate of hydrogen is 1000sccm, the air pressure in the vacuum chamber is kept at 6kPa, the distance between the filament and the sample is 9.5mm, the distance between the filament and the filament is 8mm, the temperature of the filament is 2000°C, the temperature of the substrate is 680°C, and the deposition time is 0.5 hours. A silicon carbide (SiC) layer with a thickness of 0.5 microns is formed on the treated surface, and the silicon carbide grain size is 30 nanometers;

(3) Then feed methane gas and gradually reduce the flow of dimethylsilane, keep the flow of hydrogen constant, at this time, prepare silicon carbide-diamond gradient composite coating with methane, tetramethylsilane and hydrogen as reaction gases, the specific The conditions are as follows: the methane gas flow rate initially introduced is 40 sccm, the tetramethylsilane gas flow rate is 4 sccm, the vacuum chamber pressure is reduced to 2 kPa, the distance between the filament and the sample is 8.5 mm, the distance between the filament and the filament is 8 mm, and the temperature of the filament is 2000°C , the substrate temperature is 680°C. In the preparation process, the gas flow rate of tetramethylsilane was gradually reduced until it approached zero, and the total deposition time was 6 hours to obtain a silicon carbide-diamond gradient composite coating with a thickness of 4 microns; the silicon carbide-diamond gradient composite coating Among them, the silicon carbide grain is 80nm, the diamond grain is 50nm, the silicon carbide content gradually decreases along the thickness growth direction, and the diamond content gradually increases;

(4) The flow rate of dimethylsilane is reduced to zero, and hydrogen and methane are used as reaction gases to continue to deposit nano-diamond coatings on the gradient composite coating. The deposition conditions are as follows: the distance between the filament and the sample is 8.5 mm, and the distance between the filament and the sample Filament spacing is 8 mm; methane gas flow rate is 32 sccm, hydrogen gas flow rate is 800 sccm, and the volume ratio of methane to hydrogen gas is kept at about 4%; the vacuum chamber pressure range is 2kPa; the filament temperature range is 2000°C, and the substrate temperature range is 680°C; The processing time is 6 hours, the thickness of the obtained diamond film is about 5 microns, and the grain size is about 30 nanometers;

(5) Using the physical vapor deposition method, a diamond-like coating was prepared on the diamond coating with the graphite target as the carbon source. The specific deposition conditions were as follows: firstly, the ion source was cleaned, and the background vacuum of the reaction chamber was kept at 2×10 ^-3 Pa, heat the temperature to 150°C, turn on the ion source, fill the reaction chamber with argon (Ar), adjust the input gas flow rate, keep the vacuum degree of the reaction chamber at 2×10 ^-1 Pa, bias -1200V, and last for 15 minute. Then carry out the diamond-like coating deposition, keep the vacuum degree at 3×10 ^{- 2} Pa, the temperature at 320°C, adjust the deposition bias to -600V, the ion current at 10A, the target power at 6kW, and the deposition time at 6 hours. Diamond-like carbon coating with a thickness of 5.5 microns;

After cooling with the furnace, the drawing die is taken out to obtain a drawing die with silicon carbide (SiC)-silicon carbide-diamond gradient composite coating-diamond-diamond-like carbon (DLC) coating.

Example 3

A method for preparing a wire drawing die with multiple coatings, comprising the following steps:

(1) The wire drawing die made of YT15 (WC-15% TiC) hard alloy sold in the domestic market is used as the substrate, and the substrate is first subjected to wet sandblasting of white corundum. The pressure during sandblasting is 300kPa, and the sand particle size 400 mesh, then ultrasonically clean the cemented carbide in acetone and alcohol for 10 minutes, and dry;

(2) The silicon carbide layer is deposited on the surface of the pretreated cemented carbide substrate by hot wire chemical vapor deposition, and the deposition conditions are as follows: hydrogen and monosilane are used as reaction gases, and methylsilane is controlled to account for 0.01% of the total gas volume , keep the air pressure in the vacuum chamber at 2kPa, the distance between the filament and the sample is 9 mm, the distance between the filament and the filament is 8 mm, the temperature of the filament is 2400 ° C, the temperature of the substrate is 850 ° C, the deposition time is 1 hour, and the thickness is formed on the pretreated surface A silicon carbide (SiC) layer of 0.7 microns with a SiC grain size of 40 nanometers;

(3) Then feed methane gas and gradually reduce the flow of monosilane, keeping the flow of hydrogen constant. At this time, methane, tetramethylsilane and hydrogen are used as reaction gases to prepare silicon carbide-diamond gradient composite coatings. The specific conditions are as follows : The methane gas flow rate initially introduced is 16sccm, the tetramethylsilane gas flow rate is 4sccm, the vacuum chamber pressure is reduced to 4kPa, the distance between the filament and the sample is 10mm, the distance between the filament and the filament is 8mm, the temperature of the filament is 2400°C, and the substrate The temperature is 850°C. In the preparation process, the gas flow rate of tetramethylsilane was gradually reduced until it approached zero, and the total deposition time was 1.5 hours to obtain a silicon carbide-diamond gradient composite coating with a thickness of 2.5 microns; the silicon carbide-diamond gradient composite coating Among them, the silicon carbide grain size is 70nm, the diamond grain size is 1.5-2 microns, the silicon carbide content gradually decreases along the thickness growth direction, and the diamond content gradually increases;

(4) Reduce the flow rate of monosilane to zero, and continue to deposit nano-diamond coatings on the gradient composite coating with hydrogen and methane as reaction gases. The deposition conditions are as follows: the distance between the filament and the sample is 10 mm, and the distance between the filament and the filament The flow rate of methane gas is 24sccm, the flow rate of hydrogen gas is 800sccm, the volume ratio of methane to hydrogen is kept at about 3%; the pressure range of the vacuum chamber is 2kPa; the temperature range of the filament is 2200°C, the temperature range of the substrate is 800°C For 6 hours, the thickness of the obtained diamond film is about 5 microns, and the grain size is about 30 nanometers;

(5) Using the physical vapor deposition method, using the graphite target as the carbon source, prepare a layer of diamond-like coating on the diamond coating. The specific deposition conditions are as follows: first, clean the ion source and keep the background vacuum of the reaction chamber at 1 × 10 ^-3 Pa, heat the temperature to 140°C, turn on the ion source, fill the reaction chamber with argon (Ar), adjust the input gas flow rate, and keep the vacuum degree of the reaction chamber at 3×10 ^-1 Pa, bias -1000V, continuous 30 minutes. Then carry out diamond-like coating deposition, keep the vacuum at 1×10 ^{- 2} Pa, the temperature at 340°C, adjust the deposition bias to -300V, the ion current at 12A, the target power at 3.6kW, and the deposition time at 4 hours. Obtain a diamond-like coating with a thickness of 4.5 microns; after cooling with the furnace, take out the wire-drawing die to obtain a wire-drawing die with silicon carbide (SiC)-silicon carbide-diamond gradient composite coating-diamond-diamond-like carbon (DLC) coating .

Example 4

A method for preparing a wire drawing die with multiple coatings, comprising the following steps:

(1) The ceramic wire drawing die sold in the domestic market is used as the substrate. First, the substrate is subjected to wet sandblasting of white corundum. The pressure during sandblasting is 350kPa, and the sand particle size is 600 mesh. Superalloy ultrasonic cleaning for 20 minutes, drying;

(2) adopt the hot wire chemical vapor deposition method to deposit silicon carbide layer on the cemented carbide substrate surface after pretreatment, its deposition condition is as follows: organosilane gas flow rate is 4sccm, hydrogen gas flow rate is 800sccm, and the air pressure that keeps vacuum chamber is 5kPa , the distance between the filament and the sample is 9.5 mm, the distance between the filament and the filament is 8 mm, the temperature of the filament is 2800 ° C, the temperature of the substrate is 1000 ° C, the deposition time is 2 hours, and a silicon carbide (SiC ) layer, the silicon carbide grain size is 80 nanometers;

(3) Then feed methane gas and gradually reduce the flow of tetramethylsilane, keep the flow of hydrogen constant, at this time, prepare silicon carbide-diamond gradient composite coating with methane, tetramethylsilane and hydrogen as reaction gases, the specific The conditions are as follows: the methane gas flow rate initially introduced is 16 sccm, the tetramethylsilane gas flow rate is 4 sccm, the vacuum chamber pressure is reduced to 4 kPa, the distance between the filament and the sample is 10 mm, the distance between the filament and the filament is 8 mm, and the temperature of the filament is 1900 °C , the substrate temperature is 700°C, the gas flow rate of tetramethylsilane is gradually reduced during the preparation process until it approaches zero, the total deposition time is 2 hours, and a silicon carbide-diamond gradient composite coating with a thickness of 3 microns is obtained; the carbonization In the silicon-diamond gradient composite coating, the silicon carbide grain size is 30nm, the diamond grain size is 0.5 micron, and the silicon carbide content gradually decreases along the thickness growth direction while the diamond content gradually increases;

(4) Reduce the tetramethylsilane flow rate to zero, use hydrogen and methane as reaction gases, and continue to deposit nano-diamond coatings on the gradient composite coating. The deposition conditions are as follows: the distance between the filament and the sample is 8.5 mm, and the distance between the filament and the filament The spacing is 10mm; the flow rate of methane gas is 16sccm, the flow rate of hydrogen gas is 800sccm, and the volume ratio of methane to hydrogen is kept at about 2%; the pressure range of the vacuum chamber is 4kPa; the temperature range of the filament is 2200°C, and the temperature range of the substrate is 800°C; The time is 4 hours, the thickness of the obtained diamond coating is about 5 microns, and the grain size is 2 microns;

(5) Using the physical vapor deposition method, a diamond-like coating was prepared on the diamond coating with the graphite target as the carbon source. The specific deposition conditions were as follows: firstly, the ion source was cleaned, and the background vacuum of the reaction chamber was kept at 3×10 ^-3 Pa, heat the temperature to 160°C, turn on the ion source, fill the reaction chamber with argon (Ar), adjust the input gas flow rate, and keep the vacuum degree of the reaction chamber at 1×10 ^-1 Pa, bias -1200V for 30 minute. Then the diamond-like coating was deposited, keeping the vacuum at 5×10 ^{- 2} Pa, the temperature at 350°C, adjusting the deposition bias to -400V, the ion current at 11A, the target power at 7.2kW, and the deposition time at 6 hours. Obtain a diamond-like carbon coating with a thickness of 5.8 microns;

After cooling with the furnace, the drawing die is taken out to obtain a drawing die with silicon carbide (SiC)-silicon carbide-diamond gradient composite coating-diamond-diamond-like carbon (DLC) coating.

It should be noted that, according to the disclosure and explanation of the above specification, those skilled in the art to which the present application belongs may also make changes and modifications to the above implementation manner. Therefore, the present application is not limited to the specific implementation manners disclosed and described above, and some equivalent modifications and changes to the present application should also fall within the scope of protection of the claims of the present application. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present application.

Claims (5)

1. A wire drawing die with multiple coatings, characterized in that it comprises a wire drawing die substrate, and a silicon carbide layer, a silicon carbide-diamond gradient composite coating, a diamond coating and In the diamond-like coating, in the silicon carbide-diamond gradient composite coating, along the thickness direction from the silicon carbide layer to the diamond coating, the content of silicon carbide gradually decreases while the content of diamond gradually increases. 2. The wire drawing die with multiple coatings as claimed in claim 1, wherein the thickness of the diamond-like coating is 2-6 microns. 3. The wire drawing die with multiple coatings as claimed in claim 1, wherein the thickness of the silicon carbide layer is 0.5-2 microns, and the silicon carbide grain size in the silicon carbide layer is nanoscale . 4. The wire drawing die with multiple coatings as claimed in claim 1, wherein the thickness of the silicon carbide-diamond gradient composite coating is 2-5 microns; the silicon carbide-diamond gradient composite coating Among them, the silicon carbide grain size is at the nanometer level, and the diamond grain size is at the nanometer or micron level. 5. The wire drawing die with multiple coatings as claimed in claim 1, characterized in that, the thickness of the diamond coating is 2-8 microns, and the diamond crystal grains of the diamond coating are at the nanometer or micron level.