Preparation process of TiN coating with high binding force

Abstract

The invention relates to the technical field of high-binding-force coating preparation, in particular to a high-binding-force TiN coating preparation technology which comprises the following steps that S1, a base body is pretreated; the pretreatment comprises grinding treatment, polishing treatment and cleaning treatment; s2, the pretreated base body is put into a vacuum cavity, the vacuum degree in the vacuum cavity is adjusted, and then the pretreated base body is subjected to heating treatment; s3, carrying out bias cleaning and ion etching treatment on the substrate in the vacuum cavity; s4, high-purity nitrogen is introduced into the vacuum cavity, then sputtering treatment is conducted through the HiPIMS technology, and a TiN coating is deposited on the surface of the base body; and S5, the vacuumizing system is closed, the vacuum cavity is cooled, then the base body is taken out, and the base body with the TiN coating on the surface is obtained. According to the preparation process, the reliability of the coating under the high-load condition can be improved, and the interface characteristics of the coating are improved.

Description

Technical Field

[0001] The invention relates to the technical field of high-bonding strength coating preparation, and in particular to a preparation process of a high-bonding strength TiN coating. Background Art

[0002] Titanium nitride (TiN) coatings are widely used in cutting tools, molds, medical devices, aerospace and other fields due to their high hardness, excellent wear resistance, corrosion resistance and good thermal stability. However, the insufficient bonding strength between TiN coatings and substrates has always been one of the main factors limiting their practical applications. Under high stress environments, TiN coatings may peel off or crack, significantly reducing their service life and performance.

[0003] The bonding strength of TiN coating is affected by many factors, including the pretreatment method of the substrate, the coating deposition method, the deposition temperature and the gas composition ratio. In the prior art, most studies focus on improving the hardness and wear resistance of TiN coating, while the study on the influence of nitrogen and argon ratio on the bonding strength of TiN coating is still insufficient. Although the increase of nitrogen can promote the formation of TiN, too high nitrogen content may lead to an increase in residual stress in the TiN coating, thereby weakening the bonding strength between the TiN coating and the substrate. On the contrary, the appropriate increase in argon content can reduce the internal stress generated during the deposition process and improve the bonding performance of the TiN coating, but too high argon content may hinder the formation of TiN and reduce the generation efficiency of the TiN coating. At present, the existing technical solutions for preparing TiN coatings still lack systematic research on the range of nitrogen and argon ratios in the gas, the specific mechanism of action and their application in improving bonding strength. There is no clear technical solution to publicly explain the relationship between the optimized range of nitrogen and argon ratios in the gas and the bonding strength of the TiN coating. Therefore, it is urgent to develop a method for improving the bonding strength of TiN coating by adjusting the nitrogen and argon ratio in the gas.

[0004] The invention provides a preparation process of a TiN coating with high bonding strength, so as to solve the problems existing in the prior art that the existing TiN coating preparation process lacks a specific study on the influence of the ratio of nitrogen to argon in the gas and the range of the ratio of nitrogen to argon on the bonding strength of the TiN coating, and the bonding strength of the TiN coating is insufficient. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation process of a high-bonding strength TiN coating to solve the problems existing in the prior art of the existing TiN coating preparation process, such as the lack of specific research on the influence of the nitrogen-argon ratio and the range of the nitrogen-argon ratio in the gas on the bonding strength of the TiN coating, and the insufficient bonding strength of the TiN coating.

[0006] The technical solution of the present invention is: a preparation process of a high-bonding TiN coating, comprising the following steps:

[0007] S1, pre-treating the substrate; the pre-treatment includes grinding, polishing and cleaning;

[0008] S2. Place the pretreated substrate into the vacuum chamber used by HiPIMS and adjust the vacuum degree in the vacuum chamber to 8.0×10 -2 Pa~3.0×10 -2 Pa range, then, turn on the heating switch to raise the temperature in the vacuum chamber to a range of 380-420°C, and perform a temperature treatment on the pretreated substrate;

[0009] S3, performing bias cleaning and ion etching on the substrate in the vacuum chamber;

[0010] S4, introducing high-purity nitrogen into the vacuum chamber, and controlling the flow ratio of nitrogen to argon in the range of 1: (3.3-8.3), and then performing sputtering treatment using HiPIMS technology to deposit a TiN coating on the surface of the substrate;

[0011] S5. Turn off the vacuum system and cool the vacuum cavity to reduce the temperature inside the vacuum cavity to below 120° C. Then, take the substrate out of the cooled vacuum cavity to obtain a substrate with a TiN coating on the surface.

[0012] Preferably, the substrate is made of cemented carbide material.

[0013] Preferably, in step S1, the grinding treatment includes mechanical grinding using 1000 mesh, 2000 mesh, and 3000 mesh diamond grinding wheels in sequence; the polishing treatment is performed using 0.1-0.2 μm polishing paste and velvet polishing cloth; and the cleaning treatment includes ultrasonic cleaning using alcohol and acetone.

[0014] Preferably, in step S3, the bias cleaning and ion etching process comprises the following steps:

[0015] a. Adjust the vacuum degree in the vacuum chamber to 3.0×10 -3 After the vacuum chamber reaches 15 Pa, 200-500 sccm of high-purity argon gas is introduced into the vacuum chamber. After that, the throttle valve angle of the vacuum chamber is adjusted to 10-30° to make the vacuum in the vacuum chamber reach 10-15 Pa.

[0016] b. Turn on the bias power supply and set the bias power supply working parameters to: voltage of -600 to -800 V, frequency of 0.5 to 1 kHz, pulse width of 50 to 80 μs, and perform bias cleaning on the substrate. The cleaning time is controlled within the range of 10 to 15 minutes.

[0017] c. After the bias cleaning is completed, the bias power supply operating parameters are adjusted to: voltage of -300 to -500 V, frequency of 4 to 6 kHz, and pulse width of 50 to 80 μs; then, the arc electron source power supply is turned on, and the operating parameters of the arc electron source are set to: current of 60 to 80 A, voltage of 15 to 25 V;

[0018] d. Turn on the arc electron source auxiliary anode power supply, the sputtering target is a Ti target, and the working parameters of the auxiliary anode power supply are: current of 30-50A, voltage of 40-60V, the substrate surface is ion etched, and the etching time is controlled within the range of 10-20min.

[0019] Preferably, the size of the Ti target is Φ48×33 mm; the purity of the Ti target is 99.999%.

[0020] Preferably, in step S4, during the sputtering process, the bias parameters of the substrate are set to: voltage of -120 to -150 V, frequency of 5 to 8 kHz, and pulse width of 60 to 90 μs; the parameters of the medium frequency Ti target power supply used are set to: voltage of 400 to 500 V, current of 80 to 100 A, and average power of the target power supply of 3.2 to 5.0 kW.

[0021] Preferably, in step S4, during the sputtering process, the working gas pressure in the vacuum chamber is set to 0.4-0.6 Pa; and the sputtering time of the sputtering process is 60 minutes.

[0022] Preferably, the size of the medium frequency Ti target is 100×1000×10 mm; the purity of the medium frequency Ti target is 99.999%.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] (1) The present invention provides a preparation process of a high-bonding strength TiN coating. In the preparation process of the TiN coating, the ratio of nitrogen to argon is optimized to enhance the compactness and interface bonding strength of the TiN coating, reduce the peeling phenomenon of the TiN coating, and further improve the reliability of the TiN coating under high load conditions and improve the interface characteristics of the TiN coating. Moreover, by regulating the nitrogen to argon ratio in the gas, not only the chemical composition of the TiN coating can be optimized, but also the physical interface morphology between the TiN coating and the substrate can be improved, interface defects can be reduced, and the bonding strength of the TiN coating can be enhanced. Thus, the balance between the hardness and bonding strength of the TiN coating can be achieved, and the service life of the TiN coating can be extended. In addition, the nitrogen to argon ratio optimization method proposed in the present application can be applied to a variety of coating preparation equipment such as PVD and magnetron sputtering, without the need to add an additional bonding layer or change the substrate material, the process operation is simple, and it is suitable for industrial large-scale production. It solves the problems existing in the prior art that the existing TiN coating preparation process lacks a specific study on the influence of the nitrogen to argon ratio and the range of the nitrogen to argon ratio in the gas on the bonding strength of the TiN coating, and the bonding strength of the TiN coating is insufficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0026] Figure 1 A comparison diagram of the surface coating morphology of substrates P1-P3 having TiN coatings on their surfaces prepared in Examples 1-3 of the present invention;

[0027] Figure 2 A comparison chart of the loading force-friction force test results of substrates P1-P3 with TiN coatings on their surfaces prepared in Examples 1-3 of the present invention;

[0028] Figure 3 This is a comparison diagram of the scratch morphologies of substrates P1-P3 with TiN coatings on their surfaces prepared in Examples 1-3 of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with specific embodiments:

[0030] Example 1

[0031] A method for preparing a high-bonding strength TiN coating provided in the present application is used to sputter a layer of TiN coating on the surface of a substrate; specifically, the method comprises the following steps:

[0032] S1, pre-treating the substrate; the pre-treatment includes grinding, polishing and cleaning;

[0033] First, the substrate is mechanically polished using 1000 mesh, 2000 mesh, and 3000 mesh diamond grinding discs respectively; then the mechanically polished substrate is polished using 0.2 μm polishing paste and velvet polishing cloth; then, the polished substrate is first placed in acetone for ultrasonic cleaning for 15 minutes, and then the substrate cleaned with acetone is placed in alcohol for ultrasonic cleaning for 15 minutes; after cleaning, the substrate is placed in a dust-free environment for drying and dehydration. In this embodiment or the gas embodiment, the substrate is made of cemented carbide material.

[0034] S2. Place the pretreated substrate into the vacuum chamber used by HiPIMS and adjust the vacuum degree in the vacuum chamber to 8.0×10 -2 Pa; then, turn on the heating switch, raise the temperature in the vacuum chamber to within 400°C, and perform a temperature treatment on the pretreated substrate.

[0035] S3, performing bias cleaning and ion etching on the substrate in the vacuum chamber; specifically comprising the following steps:

[0036] a. First adjust the vacuum degree in the vacuum chamber to 3.0×10 -3 Pa, then 500 sccm of high-purity argon gas was introduced into the vacuum chamber, and then the throttle valve angle of the vacuum chamber was adjusted to 10° to make the vacuum in the vacuum chamber reach 10Pa;

[0037] b. Turn on the bias power supply and set the bias power supply working parameters to: voltage of -800 V, frequency of 0.6 kHz, pulse width of 80 μs, and perform bias cleaning on the substrate. The cleaning time is controlled within the range of 10 to 15 minutes.

[0038] c. After the bias cleaning is completed, the bias power supply operating parameters are adjusted to: voltage of -300V, frequency of 5.8kHz, pulse width of 80μs; ​​then, the arc electron source power supply is turned on, and the operating parameters of the arc electron source are set to: current of 80A, voltage of 19.2V;

[0039] d. Turn on the arc electron source auxiliary anode power supply, the sputtering target is a Ti target, and the working parameters of the auxiliary anode power supply are: the current is 35A, the voltage is 42.3V, and the substrate surface is ion-etched for 15 minutes. In this embodiment or the gas embodiment, the size of the Ti target used in the ion etching process can be Φ48×33mm; the purity of the Ti target needs to reach 99.999%.

[0040] S4. High-purity nitrogen is introduced into the vacuum chamber, and the flow ratio of nitrogen to argon is controlled at 1:3.3. After that, the HiPIMS technology is used for sputtering treatment to deposit a TiN coating on the surface of the substrate. In the process of sputtering treatment, the bias parameters of the substrate are set to: voltage of -120V, frequency of 6.8kHz, and pulse width of 80μs; ​​the parameters of the medium-frequency Ti target power supply used are set to: voltage of 440V, current of 95.8A, and average power of the target power supply of 3.3kw; and, in the process of sputtering treatment, the working gas pressure in the vacuum chamber is set to 0.52Pa; the sputtering time of the sputtering treatment is 60min. In addition, in this embodiment or gas embodiment, the size of the medium-frequency Ti target used is 100×1000×10mm, and the purity of the medium-frequency Ti target needs to reach 99.999%.

[0041] S5. Turn off the vacuum system and cool the vacuum chamber to reduce the temperature inside the vacuum chamber to below 120° C. Then, take the substrate out of the cooled vacuum chamber to obtain a substrate with a TiN coating on the surface, P1.

[0042] Example 2

[0043] A method for preparing a high-bonding strength TiN coating provided in the present application is used to sputter a layer of TiN coating on the surface of a substrate; specifically, the method comprises the following steps:

[0044] S1. Pre-treating the substrate; the pre-treatment includes grinding, polishing and cleaning. First, mechanically grinding the substrate with diamond grinding discs of 1000 mesh, 2000 mesh and 3000 mesh respectively; then polishing the mechanically ground substrate with 0.2 μm polishing paste and velvet polishing cloth; then, firstly putting the polished substrate into acetone for ultrasonic cleaning for 15 minutes, and then putting the substrate cleaned with acetone into alcohol for ultrasonic cleaning for 15 minutes; after cleaning, putting the substrate into an oven for drying and dehydration.

[0045] S2. Place the pretreated substrate into the vacuum chamber used by HiPIMS and adjust the vacuum degree in the vacuum chamber to 8.0×10 -2 Pa; then, turn on the heating switch, raise the temperature in the vacuum chamber to within 400°C, and perform a temperature-raising treatment on the pretreated substrate.

[0046] S3, performing bias cleaning and ion etching on the substrate in the vacuum chamber; specifically comprising the following steps:

[0047] a. First adjust the vacuum degree in the vacuum chamber to 3.0×10 -3Pa, then 500 sccm of high-purity argon gas was introduced into the vacuum chamber, and then the throttle valve angle of the vacuum chamber was adjusted to 10° to make the vacuum in the vacuum chamber reach 10Pa;

[0048] b. Turn on the bias power supply and set the bias power supply working parameters to: voltage of -800 V, frequency of 0.6 kHz, pulse width of 80 μs, and perform bias cleaning on the substrate. The cleaning time is controlled within the range of 10 to 15 minutes.

[0049] c. After the bias cleaning is completed, the bias power supply operating parameters are adjusted to: voltage of -300V, frequency of 5.8kHz, pulse width of 80μs; ​​then, the arc electron source power supply is turned on, and the operating parameters of the arc electron source are set to: current of 80A, voltage of 19.2V;

[0050] d. Turn on the arc electron source auxiliary anode power supply, the sputtering target is a Ti target, and the working parameters of the auxiliary anode power supply are: the current is 35A and the voltage is 42.3V. The substrate surface is ion etched for 15 minutes.

[0051] S4. High-purity nitrogen is introduced into the vacuum chamber, and the flow ratio of nitrogen to argon is controlled at 1:5. Then, the HiPIMS technology is used for sputtering to deposit a TiN coating on the surface of the substrate. During the sputtering process, the bias parameters of the substrate are set to: voltage of -120V, frequency of 6.8kHz, and pulse width of 80μs; ​​the parameters of the medium-frequency Ti target power supply used are set to: voltage of 440V, current of 95.8A, and average power of the target power supply of 3.3kw; and during the sputtering process, the working gas pressure in the vacuum chamber is set to 0.52Pa; the sputtering time of the sputtering process is 60min.

[0052] S5. Turn off the vacuum system and cool the vacuum chamber to reduce the temperature inside the vacuum chamber to below 120° C. Then, take the substrate out of the cooled vacuum chamber to obtain a substrate with a TiN coating on the surface, P2.

[0053] Example 3

[0054] A method for preparing a high-bonding strength TiN coating provided in the present application is used to sputter a layer of TiN coating on the surface of a substrate; specifically, the method comprises the following steps:

[0055] S1. Pre-treat the substrate; the pre-treatment includes grinding, polishing and cleaning. First, mechanically grind the substrate with diamond grinding discs of 1000 mesh, 2000 mesh and 3000 mesh respectively; then polish the mechanically grinded substrate with 0.2 μm polishing paste and velvet polishing cloth; then, put the polished substrate into acetone for ultrasonic cleaning for 15 minutes, and then put the substrate cleaned with acetone into alcohol for ultrasonic cleaning for 15 minutes; after cleaning, wipe the surface of the substrate and dry it.

[0056] S2. Place the pretreated substrate into the vacuum chamber used by HiPIMS and adjust the vacuum degree in the vacuum chamber to 8.0×10 -2 Pa; then, turn on the heating switch to raise the temperature in the vacuum chamber to 400°C, and heat the pretreated substrate.

[0057] S3, performing bias cleaning and ion etching on the substrate in the vacuum chamber; specifically comprising the following steps:

[0058] a. First adjust the vacuum degree in the vacuum chamber to 3.0×10 -3 Pa, then 500 sccm of high-purity argon gas was introduced into the vacuum chamber, and then the throttle valve angle of the vacuum chamber was adjusted to 10° to make the vacuum in the vacuum chamber reach 10Pa;

[0059] b. Turn on the bias power supply and set the bias power supply working parameters to: voltage of -800 V, frequency of 0.6 kHz, pulse width of 80 μs, and perform bias cleaning on the substrate. The cleaning time is controlled within the range of 10 to 15 minutes.

[0060] c. After the bias cleaning is completed, the bias power supply operating parameters are adjusted to: voltage of -300V, frequency of 5.8kHz, pulse width of 80μs; ​​then, the arc electron source power supply is turned on, and the operating parameters of the arc electron source are set to: current of 80A, voltage of 19.2V;

[0061] d. Turn on the arc electron source auxiliary anode power supply, the sputtering target is a Ti target, and the substrate surface is ion-etched under the working parameters of the auxiliary anode power supply: the current is 35A and the voltage is 42.3V. The etching time is 15 minutes. The size of the Ti target used in the ion etching process is Φ48×33mm; the purity of the Ti target is 99.999%.

[0062] S4. High-purity nitrogen is introduced into the vacuum chamber, and the flow ratio of nitrogen to argon is controlled at 1:8.3. Then, the HiPIMS technology is used for sputtering to deposit a TiN coating on the surface of the substrate. During the sputtering process, the bias parameters of the substrate are set to: voltage of -120V, frequency of 6.8kHz, and pulse width of 80μs; ​​the parameters of the medium-frequency Ti target power supply used are set to: voltage of 440V, current of 95.8A, and average power of the target power supply of 3.3kw; and during the sputtering process, the working gas pressure in the vacuum chamber is set to 0.52Pa; the sputtering time of the sputtering process is 60min.

[0063] S5. Turn off the vacuum system and cool the vacuum chamber to reduce the temperature inside the vacuum chamber to below 120° C. Then, take the substrate out of the cooled vacuum chamber to obtain a substrate with a TiN coating on the surface, P3.

[0064] The substrates P1-P3 with TiN coatings on the surfaces prepared in Examples 1-3 were tested using a testing instrument to test the compactness of the TiN coatings, the bonding performance of the TiN coatings with the substrates, etc. Figure 1 As shown, from the comparison diagram of the surface coating morphology of the substrates P1-P3 with TiN coating on the surface prepared by Examples 1-3, it can be seen that the TiN coating on the surface of the substrates P1-P3 with TiN coating on the surface prepared by Examples 1-3 has good density and uniformity; and, when the ratio of nitrogen to argon in the gas in the vacuum chamber is 1:5 and 1:8.3, the surface quality of the coating is higher; furthermore, when other process parameters are controlled unchanged, only the ratio of nitrogen to argon in the gas in the vacuum chamber is adjusted, which can significantly affect the microstructure of the coating and improve the physical interface morphology between the coating and the substrate, thereby enhancing the density of the coating, reducing the residual stress in the coating, and making the residual stress in the coating uniformly distributed, thereby improving the bonding strength between the coating and the substrate. By performing a loading force-friction force test on the substrates P1-P3 with TiN coating on the surface prepared by Examples 1-3, as shown Figure 2 As shown, when the ratio of nitrogen to argon in the vacuum chamber is 1:8.3, the friction mutation point of the prepared substrate P3 with a TiN coating on the surface is higher, that is, the critical load of the TiN coating on the surface is higher, and the bonding force between the TiN coating on the surface and the substrate is higher; and Figure 3As shown, it can be seen from the scratch morphology comparison diagram that when the ratio of nitrogen to argon in the gas in the vacuum chamber is 1:8.3, the prepared substrate P3 with a TiN coating on the surface has better wear resistance and coating hardness; further illustrating that by adjusting the ratio of nitrogen to argon in the gas in the vacuum chamber, the interface bonding performance of the TiN coating can be adjusted; thereby significantly improving the bonding strength between the TiN coating and the substrate, achieving a balance between the hardness and bonding force of the TiN coating, and extending the service life of the coating; solving the problem of insufficient bonding force of the TiN coating in the prior art.

[0065] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the scope of protection of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A process for preparing a high-bonding TiN coating, characterized in that: The following steps are involved: S1, pre-treating the substrate; the pre-treatment includes grinding, polishing and cleaning; S2. Place the pretreated substrate into the vacuum chamber used by HiPIMS and adjust the vacuum degree in the vacuum chamber to 8.0×10 -2 Pa~3.0×10 -2 Pa range, then, turn on the heating switch to raise the temperature in the vacuum chamber to a range of 380-420°C, and perform a temperature treatment on the pretreated substrate; S3, performing bias cleaning and ion etching on the substrate in the vacuum chamber; S4, introducing high-purity nitrogen into the vacuum chamber, and controlling the flow ratio of nitrogen to argon in the range of 1: (3.3-8.3), and then performing sputtering treatment using HiPIMS technology to deposit a TiN coating on the surface of the substrate; S5. Turn off the vacuum system and cool the vacuum cavity to reduce the temperature inside the vacuum cavity to below 120° C. Then, take the substrate out of the cooled vacuum cavity to obtain a substrate with a TiN coating on the surface.

2. The process for preparing a high-bonding strength TiN coating according to claim 1, characterized in that: The matrix is ​​made of hard alloy material.

3. The process for preparing a high-bonding strength TiN coating according to claim 2, characterized in that: In step S1, the grinding treatment includes mechanical grinding using 1000 mesh, 2000 mesh, and 3000 mesh diamond grinding discs in sequence; the polishing treatment is performed using 0.1-0.2 μm polishing paste and velvet polishing cloth; and the cleaning treatment includes ultrasonic cleaning using alcohol and acetone.

4. The process for preparing a high-bonding strength TiN coating according to claim 2, characterized in that: In step S3, the bias cleaning and ion etching process includes the following steps: a. Adjust the vacuum degree in the vacuum chamber to 3.0×10 -3 After the vacuum chamber reaches 15 Pa, 200-500 sccm of high-purity argon gas is introduced into the vacuum chamber. After that, the throttle valve angle of the vacuum chamber is adjusted to 10-30° to make the vacuum in the vacuum chamber reach 10-15 Pa. b. Turn on the bias power supply and set the bias power supply working parameters to: voltage of -600 to -800 V, frequency of 0.5 to 1 kHz, pulse width of 50 to 80 μs, and perform bias cleaning on the substrate. The cleaning time is controlled within the range of 10 to 15 minutes. c. After the bias cleaning is completed, the bias power supply operating parameters are adjusted to: voltage of -300 to -500 V, frequency of 4 to 6 kHz, and pulse width of 50 to 80 μs; then, the arc electron source power supply is turned on, and the operating parameters of the arc electron source are set to: current of 60 to 80 A, voltage of 15 to 25 V; d. Turn on the arc electron source auxiliary anode power supply, the sputtering target is a Ti target, and the working parameters of the auxiliary anode power supply are: current of 30-50A, voltage of 40-60V, the substrate surface is ion etched, and the etching time is controlled within the range of 10-20min.

5. The process for preparing a high-bonding strength TiN coating according to claim 4, characterized in that: The size of the Ti target is Φ48×33 mm; the purity of the Ti target is 99.999%.

6. The process for preparing a high-bonding strength TiN coating according to claim 2, characterized in that: In step S4, during the sputtering process, the bias parameters of the substrate are set to: voltage of -120 to -150 V, frequency of 5 to 8 kHz, and pulse width of 60 to 90 μs; the parameters of the medium frequency Ti target power supply used are set to: voltage of 400 to 500 V, current of 80 to 100 A, and average power of the target power supply of 3.2 to 5.0 kW.

7. The process for preparing a high-bonding strength TiN coating according to claim 6, characterized in that: In step S4, during the sputtering process, the working gas pressure in the vacuum chamber is set to 0.4-0.6 Pa; the sputtering time of the sputtering process is 60 minutes.

8. The process for preparing a high-bonding strength TiN coating according to claim 6, characterized in that: The size of the intermediate frequency Ti target is 100×1000×10 mm; the purity of the intermediate frequency Ti target is 99.999%.

Images