TiN wear-resistant coating with nano composite gradient structure and preparation method of TiN wear-resistant coating

Abstract

The invention discloses a TiN wear-resistant coating with a nano-composite gradient structure and a preparation method of the TiN wear-resistant coating. The problems that a traditional TiN coating is insufficient in bonding strength, poor in wear resistance and the like are solved. The preparation method comprises the following steps: 1, ultrasonically cleaning the substrate; 2, loading the chip; 3, vacuumizing the vacuum bin; 4, plasma cleaning; 5, coating pre-deposition; 6, turning on a multi-arc power supply, and controlling periodic changes of argon flow and nitrogen flow in stages for vapor deposition to obtain a TiN coating; and 7, cooling. The TiN coating with the nano-composite gradient structure is formed by multi-arc ion plating deposition, in the deposition direction, the nitrogen element content has periodic gradient change, and the gradient is of the nano-grade gradient structure formed by compounding a clockwise gradient with the gradually-increased nitrogen content and an anticlockwise gradient with the gradually-decreased nitrogen content. According to the nano composite gradient structure, the attribute difference between a coating material and a matrix can be remarkably reduced, the residual stress in the coating is reduced, and the bonding strength and wear resistance of the coating are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of surface protective coatings and preparation thereof, and particularly relates to a TiN coating with nano-scale composite gradient and good wear resistance and a preparation method thereof. Background Art

[0002] Under the macro trend of deep integration and coordinated development of the global manufacturing industry, the pursuit of efficiency, stability and precision in the industrial production process has become a key indicator system for measuring the core competitiveness of enterprises. In modern industrial production, many mechanical parts and tools face severe wear challenges, which significantly affect the normal operation of equipment, shorten their service life, and increase maintenance costs and resource consumption. Wear-resistant coatings, as an effective surface protection method, can significantly improve the wear resistance of the material surface, thereby improving the reliability and durability of mechanical parts. They have been widely used in many fields such as aerospace, automobile manufacturing, mold processing, and electronic information.

[0003] TiN coating has become one of the earliest and most widely used hard coatings for industrial applications due to its high hardness, good chemical stability, low friction coefficient and golden appearance. Traditional TiN coatings are usually prepared by physical vapor deposition (PVD). However, with the rapid development of industrial technology, the requirements for coating performance are becoming increasingly stringent, and traditional TiN coatings have gradually exposed their limitations in some aspects.

[0004] On the one hand, the single structure of the traditional TiN coating makes it easy for the coating to have insufficient bonding strength with the substrate when it is subjected to complex loads. In actual service, especially under harsh working conditions such as high stress and high impact, the coating is prone to peeling and cannot fully play its protective role. On the other hand, it is difficult to balance the hardness and toughness of the traditional TiN coating. Although the simple pursuit of high hardness can improve the wear resistance to a certain extent, it will lead to increased brittleness of the coating. When subjected to impact or alternating stress, cracks are prone to occur inside the coating and expand rapidly, eventually causing the coating to fail.

[0005] In order to overcome the shortcomings of the above-mentioned traditional TiN coatings, researchers have tried to improve them in various ways. For example, other elements are introduced into the TiN coating to form a multi-component composite coating to improve the coating's organizational structure and performance. However, these methods often only improve certain aspects of the coating's performance to a certain extent, and fail to fundamentally solve the problem of insufficient coating bonding strength. Therefore, the development of a TiN wear-resistant coating with a new structure that can significantly improve the overall performance and its preparation method are of great practical significance for meeting the modern industry's demand for high-performance wear-resistant coatings. Summary of the invention

[0006] The present invention aims to solve the problems of insufficient bonding strength and poor wear resistance existing in traditional TiN coatings, and provides a TiN coating with a nano-composite gradient structure and good wear resistance and a preparation method thereof.

[0007] The TiN wear-resistant coating with a nano-composite gradient structure of the present invention uses pure titanium as a target, and a TiN wear-resistant coating is deposited by a multi-arc ion plating process. The TiN wear-resistant coating has a nano-composite gradient structure, and the nano-composite gradient structure means that in the deposition direction, the nitrogen element content has a periodic gradient change.

[0008] The TiN wear-resistant coating with a nano-composite gradient structure of the present invention has a nano-scale gradient structure composed of a forward gradient with a gradually increasing nitrogen content and a reverse gradient with a gradually decreasing nitrogen content in the deposition direction.

[0009] The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure of the present invention is realized according to the following steps:

[0010] S1. Substrate treatment:

[0011] The substrate is ultrasonically cleaned and the cleaned substrate is obtained after drying.

[0012] S2. Loading the substrate:

[0013] The cleaned substrate is loaded on a rotating fixture and sent into the vacuum chamber of the multi-arc ion plating device, and then vacuum is pumped.

[0014] S3. Heating:

[0015] The vacuum chamber is heated to 200 - 205 °C and vacuum is pumped again.

[0016] S4. Substrate cleaning:

[0017] Argon is introduced into the vacuum chamber to perform plasma cleaning on the cleaned substrate.

[0018] S5. Coating pre-deposition:

[0019] Using titanium metal as a target, increasing the flow rate of argon, controlling the deposition pressure to be 1.0 - 1.5 Pa, setting the voltage of the bias power supply to be 100 - 200 V, turning on the bias power supply, and then turning on the multi-arc power supply to perform pre-deposition treatment.

[0020] S6. Coating deposition:

[0021] After the pre-deposition is completed, keep the multi-arc power supply on, control the flow rates of argon and nitrogen to change periodically in stages, control the total flow rate of argon and nitrogen to be 130 - 150 sccm, keep the deposition pressure to be 1.0 - 1.5 Pa, take this as a gas phase control cycle, and repeat the gas phase control cycle to perform gas phase deposition to obtain a TiN coating.

[0022] S7. Cooling:

[0023] After the vapor deposition is completed, wait for the temperature of the vacuum chamber to gradually cool down to room temperature. After introducing the atmosphere, take out the substrate, and a TiN wear-resistant coating with a nano-composite gradient structure is deposited on the substrate.

[0024] In the preparation method of the TiN wear-resistant coating with a nano-composite gradient structure of the present invention, during the coating deposition process, it is necessary to control the flow rate of nitrogen to form a nano-scale composite gradient structure. In the said preparation method, the variation range of the controlled nitrogen flow rate is 0 - 130 sccm, the variation range of the controlled argon flow rate is 20 - 150 sccm. The increase in the nitrogen (argon) flow rate, such as going through the process of 0 → 50 → 90 → 130 sccm, and the decrease process of the nitrogen (argon) flow rate correspondingly goes through 150 → 100 → 60 → 20 sccm, and the time interval for each increase or decrease in flow rate is 800 s. The periodic increase and decrease of the nitrogen flow rate result in a composite structure of a positive gradient (increasing) and an inverse gradient (decreasing) of nitrogen content in the coating deposition direction. The composite gradient structure effectively reduces the mechanical difference between the coating material and the substrate material, thereby reducing the residual stress of the coating, while ensuring the wear resistance of the coating, improving the bonding strength between the coating and the substrate. In addition, the oxides and oxide films generated during the friction process can play a certain lubricating role, thereby reducing friction and wear, and improving the mechanical properties and wear resistance of the high-entropy alloy coating.

[0025] The TiN wear-resistant coating with a nano-composite gradient structure of the present invention and its preparation method have the following beneficial effects:

[0026] 1. The present invention provides a TiN coating with a nano-composite gradient structure and good wear resistance. The TiN coating is mainly composed of FCC phase, with uniform element distribution and no segregation phenomenon, and has broad application prospects in the field of wear-resistant coatings.

[0027] 2. The TiN coating with a nano-composite gradient structure has a composite structure of a positive gradient (increasing) and an inverse gradient (decreasing) of nitrogen content in its deposition direction, which can effectively reduce the mechanical difference between the coating material and the substrate material.

[0028] 3. This nano-composite gradient structure can effectively reduce the residual stress of the TiN coating, thereby improving the bonding strength between the coating and the substrate and enhancing the wear resistance of the coating.

[0029] 4. The TiN coating with a nano-composite gradient structure prepared by the present invention can improve the bonding strength and overall strength between the coating and the substrate, making the PVD coating exhibit excellent mechanical properties and good wear resistance. The wear rate of the TiN coating with a nano-composite gradient structure prepared by the present invention is 3.84×10-6 ~1.30×10 -5 mm 3 ·N -1 ·mm -1 。 Description of the Drawings

[0030] Figure 1 XRD spectra of the TiN coatings prepared in Examples 1 to 3;

[0031] Figure 2 Cross-sectional views of the TiN coatings prepared in Examples 1 to 3;

[0032] Figure 3 Graphs of the nitrogen content gradient changes of the TiN coatings prepared in Examples 1 to 3;

[0033] Figure 4 Schematic diagrams of three gradient changes in the nitrogen content in the TiN coatings prepared in the present invention;

[0034] Figure 5 Wear rate graphs of the TiN coatings prepared in Examples 1 to 3;

[0035] Figure 6 Residual stress graphs of the TiN coatings prepared in Examples 1 to 3. Detailed Description of the Invention

[0036] Detailed Description 1: The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure is implemented according to the following steps:

[0037] S1. Substrate treatment:

[0038] The substrate is ultrasonically cleaned and dried to obtain the cleaned substrate;

[0039] S2. Loading the substrate:

[0040] The cleaned substrate is loaded on a rotating fixture and sent into the vacuum chamber of a multi-arc ion plating device, and the vacuum is pumped;

[0041] S3. Heating:

[0042] The vacuum chamber is heated to 200 - 205 °C, and the vacuum is pumped again;

[0043] S4. Substrate cleaning:

[0044] Argon is introduced into the vacuum chamber to perform plasma cleaning on the cleaned substrate;

[0045] S5. Coating pre-deposition:

[0046] Using titanium metal as the target, increase the flow rate of argon gas, control the deposition pressure to be 1.0 - 1.5 Pa, set the voltage of the bias power supply to be 100 - 200 V, turn on the bias power supply, and then turn on the multi-arc power supply for pre-deposition treatment;

[0047] S6. Coating deposition:

[0048] After the pre-deposition is completed, keep the multi-arc power supply on, control the periodic change of the argon gas flow rate and nitrogen gas flow rate in stages, control the total flow rate of argon gas and nitrogen gas to be 130 - 150 sccm, keep the deposition pressure at 1.0 - 1.5 Pa, take it as a gas phase control cycle, repeat the gas phase control cycle for gas phase deposition to obtain a TiN coating;

[0049] S7. Cooling:

[0050] After the gas phase deposition is completed, wait for the temperature of the vacuum chamber to gradually cool to room temperature, introduce the atmosphere, take out the substrate, and deposit a TiN wear-resistant coating with a nano-composite gradient structure on the substrate.

[0051] The TiN wear-resistant coating with a nano-composite gradient structure prepared by this embodiment has an FCC face-centered cubic phase structure, has good hardness and wear resistance, and has considerable research value and application potential in the field of high-entropy alloy coatings.

[0052] The wear rate of the TiN wear-resistant coating with a nano-composite gradient structure prepared by this embodiment is 3.84×10 -6 ~1.30×10 -5 mm 3 ·N -1 ·mm -1 , and the residual stress is -5022.44~-2566.92 MPa.

[0053] The TiN wear-resistant coating with a nano-composite gradient structure prepared by this embodiment has reasonable components, uniform coating composition, good mechanical properties and wear resistance, and meets the requirements for surface protection of materials for extreme environment components such as tools, bearings, gears, and drills.

[0054] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that in step S1, the material of the substrate is elemental metal, ceramic or alloy material.

[0055] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 1 or 2 is that in step S1, the substrate is ultrasonically cleaned with absolute ethanol or acetone, and the ultrasonic cleaning time is 20 - 30 min.

[0056] Specific Embodiment 4: The difference between this embodiment and one of Specific Embodiments 1 to 3 is that in step S3, the vacuum is pumped to a pressure of 3×10-3 Pa.

[0057] Specific Embodiment Five: The difference between this embodiment and one of Embodiments One to Four is that the process of plasma cleaning in Step S4 is as follows:

[0058] Introduce argon gas into the vacuum chamber, control the argon gas flow rate to be 17 sccm, first turn on the ion source power supply, use the ion source to clean the surface of the substrate for 10 - 20 minutes, then turn off the ion source power supply, turn on the bias power supply, and use the bias to clean for 10 - 20 minutes.

[0059] Specific Embodiment Six: The difference between this embodiment and Embodiment Five is that the ion source power supply parameters are set as follows: the current is 0.3 A, and the duty cycle is 70%.

[0060] Specific Embodiment Seven: The difference between this embodiment and Embodiment Five is that the bias power supply parameters are set as follows: the voltage is 800 V, and the duty cycle is 50%.

[0061] Specific Embodiment Eight: The difference between this embodiment and one of Embodiments One to Seven is that the multi - arc power supply parameters in Step S5 are controlled as follows: the current is 65 - 75 A, and the duty cycle is 70%.

[0062] Specific Embodiment Nine: The difference between this embodiment and one of Embodiments One to Eight is that in Step S6, keep the multi - arc power supply on, control the argon gas flow rate to gradually decrease from 150 sccm to 20 sccm in stages, and at the same time control the nitrogen gas flow rate to gradually increase from 0 sccm to 130 sccm in stages (corresponding), and keep the deposition pressure at 1.0 - 1.5 Pa, which is used as a gas - phase control cycle.

[0063] Specific Embodiment Ten: The difference between this embodiment and one of Embodiments One to Eight is that in Step S6, keep the multi - arc power supply on, control the argon gas flow rate to gradually decrease from 150 sccm to 20 sccm, and then gradually increase from 20 sccm to 150 sccm, and at the same time control the nitrogen gas flow rate to gradually increase from 0 sccm to 130 sccm, and then gradually decrease from 130 sccm to 0 sccm, and keep the deposition pressure at 1.0 - 1.5 Pa, which is used as a gas - phase control cycle.

[0064] In this embodiment, the optimization of the argon gas flow rate goes through multiple stages of 150 → 100 → 60 → 20 → 60 → 100 → 150 sccm, and the optimization of the nitrogen gas flow rate goes through multiple stages of 0 → 50 → 90 → 130 → 90 → 50 → 0 sccm.

[0065] Embodiment XI: The difference between this embodiment and one of Embodiments I to VIII is that in step S6, the multi-arc power supply is kept on, and the argon gas flow rate is controlled in stages to experience multiple stages of 150→100→60→20→60→100→150→100→60→0 sccm. At the same time, the nitrogen gas flow rate is controlled in stages (correspondingly) to experience multiple stages of 0→50→90→130→90→50→0→50→90→130 sccm, and the deposition pressure is kept at 1.0 to 1.5 Pa as a gas phase control cycle.

[0066] In this embodiment, during the gas phase deposition process, the flow rates of argon and nitrogen are periodically increased or decreased, so that the TiN coating presents a nano-scale structure with a composite of positive and inverse gradients in the deposition direction.

[0067] Embodiment XII: The difference between this embodiment and one of Embodiments I to XI is that in step S7, the thickness of the TiN wear-resistant coating with a nano-composite gradient structure is 2.0 to 3.0 μm.

[0068] Example 1: The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure in this example is implemented according to the following steps:

[0069] S1. Substrate treatment:

[0070] The substrate is ultrasonically cleaned with absolute ethanol for 20 min, and the cleaned substrate is obtained after drying. The material of the substrate is 316 stainless steel, and the size is 30 mm×20 mm×2 mm;

[0071] S2. Loading the substrate:

[0072] The cleaned substrate is loaded on a rotating fixture and sent into the vacuum chamber of the multi-arc ion plating device, and the vacuum is pumped to 5×10 -3 Pa;

[0073] S3. Heating:

[0074] The vacuum chamber is heated to 200 °C, and the vacuum is pumped again to 3×10 -3 Pa;

[0075] S4. Substrate cleaning:

[0076] Argon is introduced into the vacuum chamber, and the argon gas flow rate is controlled to be 17 sccm. First, the ion source power supply is turned on, and the surface of the substrate is cleaned with the ion source for 15 min. Then, the ion source power supply is turned off, the bias power supply is turned on, and the bias cleaning is carried out for 15 min. The bias power supply is turned off, and the substrate is subjected to plasma cleaning. The parameters of the ion source power supply are: current is 0.3 A, and the duty cycle is 70%; the parameters of the bias power supply are set as: voltage is 800 V, and the duty cycle is 50%;

[0077] S5. Coating pre - deposition:

[0078] Using titanium metal as the target, increase the argon gas flow rate to 130 sccm, control the deposition pressure to 1.0 Pa, set the voltage of the bias power supply to 100 V, turn on the bias power supply, and then turn on the multi - arc power supply. The parameters of the multi - arc power supply are: current is 75 A, duty cycle is 70%, and perform pre - deposition treatment for 3 min;

[0079] S6. Coating deposition:

[0080] After the pre - deposition is completed, keep the multi - arc power supply on. Control the argon gas flow rate through multiple stages of 150→100→60→20, and control the nitrogen gas flow rate through multiple stages of 0→50→90→130 sccm. Keep the deposition pressure at 1.0 Pa. As a gas - phase control cycle, the time for each stage in the gas - phase control cycle is 2400 s. Repeat the gas - phase control cycle for gas - phase deposition for 130 min to obtain a TiN coating;

[0081] S7. Cooling:

[0082] After the gas - phase deposition is completed, wait for the temperature of the vacuum chamber to gradually cool to room temperature. After introducing the atmosphere, take out the substrate, and deposit a TiN wear - resistant coating with a nano - composite gradient structure on the substrate.

[0083] In this example, the purity of argon gas used is 99.99%, and the purity of nitrogen gas is 99.99%.

[0084] The XRD pattern of the TiN wear - resistant coating with a nano - composite gradient structure prepared in this example is as Figure 1 shown. It can be seen that the TiN wear - resistant coating with a nano - composite gradient structure has an FCC phase structure.

[0085] The cross - section SEM image of the TiN wear - resistant coating with a nano - composite gradient structure is as Figure 2 shown. It can be known that the thickness of the TiN wear - resistant coating with a nano - composite gradient structure is 2.16 μm, and it has a nano - scale positive gradient structure.

[0086] The nitrogen content gradient change diagram of the TiN wear - resistant coating with a nano - composite gradient structure is as Figure 3 shown. Its nitrogen content gradually increases in the deposition direction.

[0087] The wear rate of the TiN wear - resistant coating with a nano - composite gradient structure is as Figure 5 shown. Its wear rate is 8.63×10 -6 mm 3 ·N -1 ·mm -1 .

[0088] The TiN wear-resistant coating with a nano-composite gradient structure has a residual stress as Figure 6 shown, and its residual stress is -2625.67 MPa.

[0089] Example 2: The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure in this example is implemented according to the following steps:

[0090] S1. Substrate treatment:

[0091] The substrate is ultrasonically cleaned with absolute ethanol for 20 min, and the cleaned substrate is obtained after drying. The material of the substrate is 316 stainless steel, and its size is 30 mm × 20 mm × 2 mm;

[0092] S2. Loading the substrate:

[0093] The cleaned substrate is loaded on a rotating fixture and sent into the vacuum chamber of a multi-arc ion plating device, and the vacuum is pumped to 5 × 10 -3 Pa;

[0094] S3. Heating:

[0095] The vacuum chamber is heated to 200 °C, and the vacuum is pumped again to 3 × 10 -3 Pa;

[0096] S4. Substrate cleaning:

[0097] Argon is introduced into the vacuum chamber, and the argon flow rate is controlled at 17 sccm. First, the ion source power supply is turned on, and the surface of the substrate is cleaned with the ion source for 15 min. Subsequently, the ion source power supply is turned off, the bias power supply is turned on, and the substrate is cleaned with the bias for 15 min. Then the bias power supply is turned off, and the substrate is subjected to plasma cleaning. The parameters of the ion source power supply are: current is 0.3 A, and the duty cycle is 70%; the parameters of the bias power supply are set as: voltage is 800 V, and the duty cycle is 50%;

[0098] S5. Coating pre-deposition:

[0099] Using titanium metal as the target, the flow rate of argon is increased to 130 sccm, the deposition pressure is controlled at 1.0 Pa, the voltage of the bias power supply is set at 100 V, the bias power supply is turned on, and then the multi-arc power supply is turned on. The parameters of the multi-arc power supply are: current is 75 A, and the duty cycle is 70%, and the pre-deposition treatment is carried out for 3 min;

[0100] S6. Coating deposition:

[0101] After the pre-deposition is completed, keep the multi-arc power supply on, control the argon gas flow rate to go through multiple stages of 150→100→60→20→60→100→150 sccm, and correspondingly control the nitrogen gas flow rate to go through multiple stages of 0→50→90→130→90→50→0 sccm. Keep the deposition pressure at 1.0 Pa. As a gas phase control cycle, the time for each stage in the gas phase control cycle is 800 s. Repeat the gas phase control cycle for gas phase deposition for 130 min to obtain a TiN coating;

[0102] S7. Cooling:

[0103] After the gas phase deposition is completed, wait for the temperature of the vacuum chamber to gradually cool down to room temperature. After introducing the atmosphere, take out the substrate, and deposit a TiN wear-resistant coating with a nano-composite gradient structure on the substrate.

[0104] For the TiN wear-resistant coating with a nano-composite gradient structure prepared in this example, its XRD pattern is as Figure 1 shown. It can be seen that the TiN wear-resistant coating with a nano-composite gradient structure has an FCC phase structure.

[0105] For the TiN wear-resistant coating with a nano-composite gradient structure, its cross-sectional SEM image is as Figure 2 shown. It can be known that the thickness of the TiN wear-resistant coating with a nano-composite gradient structure is 2.01 μm, and it has a nano-scale positive gradient structure.

[0106] For the TiN wear-resistant coating with a nano-composite gradient structure, its nitrogen content gradient change diagram is as Figure 3 shown. Its nitrogen content shows a periodic change with a positive gradient in the deposition direction.

[0107] For the TiN wear-resistant coating with a nano-composite gradient structure, its wear rate is as Figure 5 shown. Its wear rate is 1.30×10 -5 mm 3 ·N -1 ·mm -1 .

[0108] For the TiN wear-resistant coating with a nano-composite gradient structure, its residual stress is as Figure 6 shown. Its residual stress is -2566.92 MPa.

[0109] Example 3: The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure in this example is implemented according to the following steps:

[0110] S1. Substrate treatment:

[0111] The substrate was ultrasonically cleaned with absolute ethanol for 20 min, and the cleaned substrate was obtained after drying. The material of the substrate was 316 stainless steel, with dimensions of 30 mm × 20 mm × 2 mm;

[0112] S2. Loading the substrate:

[0113] The cleaned substrate was loaded onto a rotating fixture and sent into the vacuum chamber of a multi-arc ion plating device, and the vacuum was pumped down to 5 × 10 -3 Pa;

[0114] S3. Heating:

[0115] The vacuum chamber was heated to 200 °C, and the vacuum was pumped down again to 3 × 10 -3 Pa;

[0116] S4. Substrate cleaning:

[0117] Argon was introduced into the vacuum chamber, and the argon flow rate was controlled at 17 sccm. First, the ion source power supply was turned on, and the surface of the substrate was cleaned with the ion source for 15 min. Subsequently, the ion source power supply was turned off, the bias power supply was turned on, and the substrate was cleaned with the bias for 15 min. Then the bias power supply was turned off, and the substrate was subjected to plasma cleaning. The parameters of the ion source power supply were controlled as follows: current 0.3 A, duty cycle 70%; the parameters of the bias power supply were set as follows: voltage 800 V, duty cycle 50%;

[0118] S5. Coating pre-deposition:

[0119] Using titanium metal as the target, the argon flow rate was increased to 130 sccm, the deposition pressure was controlled at 1.0 Pa, the voltage of the bias power supply was set at 100 V, the bias power supply was turned on, and then the multi-arc power supply was turned on. The parameters of the multi-arc power supply were: current 75 A, duty cycle 70%, and pre-deposition treatment was carried out for 3 min;

[0120] S6. Coating deposition:

[0121] After the pre-deposition was completed, the multi-arc power supply was kept on. The argon flow rate was controlled to go through multiple stages of 150 → 100 → 60 → 20 → 60 → 100 → 150 → 100 → 60 → 0 sccm, and the nitrogen flow rate correspondingly went through multiple stages of 0 → 50 → 90 → 130 → 90 → 50 → 0 → 50 → 90 → 130 sccm. The deposition pressure was kept at 1.0 Pa. As a gas phase control cycle, the time for each stage in the gas phase control cycle was 800 s. The gas phase control cycle was repeated for gas phase deposition for 130 min to obtain a TiN coating;

[0122] S7. Cooling:

[0123] After the vapor deposition is completed, wait for the temperature of the vacuum chamber to gradually cool down to room temperature. After introducing the atmosphere, take out the substrate, and a TiN wear-resistant coating with a nano-composite gradient structure is deposited on the substrate.

[0124] The purity of argon used in this example is 99.99%, and the purity of nitrogen is 99.99%.

[0125] The XRD pattern of the nano-composite gradient structure TiN wear-resistant coating prepared in this example is as Figure 1 shown. It can be seen that the nano-composite gradient structure TiN wear-resistant coating has an FCC phase structure.

[0126] The cross-sectional SEM image of the nano-composite gradient structure TiN wear-resistant coating is as Figure 2 shown. It can be known that the thickness of the nano-composite gradient structure TiN wear-resistant coating is 2.06 μm, and it has a nano-scale positive gradient structure.

[0127] The nitrogen content gradient change diagram of the nano-composite gradient structure TiN wear-resistant coating is as Figure 3 shown. Its nitrogen content shows a composite periodic change of positive gradient and inverse gradient in the deposition direction.

[0128] The wear rate of the nano-composite gradient structure TiN wear-resistant coating is as Figure 5 shown. Its wear rate is 3.84×10 -6 mm 3 ·N -1 ·mm -1 。

[0129] The residual stress of the nano-composite gradient structure TiN wear-resistant coating is as Figure 6 shown. Its residual stress is -5022.44 MPa.

[0130] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A TiN wear-resistant coating with a nano-composite gradient structure, characterized in that The TiN wear-resistant coating with a nano-composite gradient structure uses pure titanium as the target and is deposited by a multi-arc ion plating process to form a TiN wear-resistant coating. The TiN wear-resistant coating has a nano-composite gradient structure, which means that in the deposition direction, the nitrogen element content has a periodic gradient change.

2. Preparation method of TiN wear-resistant coating with nano-composite gradient structure, characterized in that The preparation method is realized according to the following steps: S1. Substrate treatment: The substrate is ultrasonically cleaned and the cleaned substrate is obtained after drying. S2. Loading the substrate: The cleaned substrate is loaded on a rotating fixture and sent into the vacuum chamber of the multi-arc ion plating device, and then the vacuum is pumped. S3. Heating: The vacuum chamber is heated to 200 - 205 °C, and the vacuum is pumped again. S4. Substrate cleaning: Argon is introduced into the vacuum chamber to perform plasma cleaning on the cleaned substrate. S5. Coating pre-deposition: Using titanium metal as the target, increasing the flow rate of argon, controlling the deposition pressure to be 1.0 - 1.5 Pa, setting the voltage of the bias power supply to be 100 - 200 V, turning on the bias power supply, and then turning on the multi-arc power supply to perform pre-deposition treatment. S6. Coating deposition: After the pre-deposition is completed, keeping the multi-arc power supply on, controlling the flow rates of argon and nitrogen to change periodically in stages, controlling the total flow rate of argon and nitrogen to be 130 - 150 sccm, keeping the deposition pressure at 1.0 - 1.5 Pa, taking this as a gas phase control cycle, and repeating the gas phase control cycle for gas phase deposition to obtain a TiN coating. S7. Cooling: After the gas phase deposition is completed, when the temperature of the vacuum chamber gradually cools to room temperature, the atmosphere is introduced, the substrate is taken out, and a TiN wear-resistant coating with a nano-composite gradient structure is deposited on the substrate.

3. The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure according to claim 2, characterized in that In step S1, the material of the substrate is a single metal, ceramic or alloy material.

4. The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure according to claim 2, characterized in that The process of plasma cleaning in step S4 is as follows: Argon is introduced into the vacuum chamber, controlling the flow rate of argon to be 17 sccm. First, turn on the ion source power supply and use the ion source to clean the surface of the substrate for 10 - 20 min, then turn off the ion source power supply, turn on the bias power supply, and use the bias to clean for 10 - 20 min.

5. The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure according to claim 4, characterized in that Set the parameters of the ion source power supply as: current is 0.3 A, duty cycle is 70%. Set the parameters of the bias power supply as: voltage is 800 V, duty cycle is 50%.

6. The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure according to claim 2, characterized in that In step S5, control the parameters of the multi-arc power supply as: current is 65 - 75 A, duty cycle is 70%.

7. The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure according to claim 2, characterized in that In step S6, keep the multi-arc power supply on, control the flow rate of argon to gradually decrease from 150 sccm to 20 sccm in stages, and at the same time control the flow rate of nitrogen to gradually increase from 0 sccm to 130 sccm in stages, keeping the deposition pressure at 1.0 - 1.5 Pa, taking this as a gas phase control cycle.

8. The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure according to claim 2, characterized in that In step S6, keep the multi-arc power supply on, control the flow rate of argon to gradually decrease from 150 sccm to 20 sccm, and then gradually increase from 20 sccm to 150 sccm in stages, and at the same time control the flow rate of nitrogen to gradually increase from 0 sccm to 130 sccm, and then gradually decrease from 130 sccm to 0 sccm in stages, keeping the deposition pressure at 1.0 - 1.5 Pa, taking this as a gas phase control cycle.

9. The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure according to claim 2, characterized in that In step S6, keep the multi-arc power supply on, and control the argon gas flow in stages through multiple stages of 150→100→60→20→60→100→150→100→60→0 sccm. At the same time, control the nitrogen gas flow in stages corresponding to multiple stages of 0→50→90→130→90→50→0→50→90→130 sccm, and keep the deposition pressure at 1.0 - 1.5 Pa, which is used as a gas phase control cycle.

10. The preparation method of the TiN wear-resistant coating with a nano-composite gradient structure according to claim 2, characterized in that In step S7, the thickness of the TiN wear-resistant coating with a nano-composite gradient structure is 2.0 - 3.0 μm.

Images