CN103805996B - The compounding method of the first plated film of a kind of metal material surface nitriding again - Google Patents

Abstract

The invention belongs to the field of material surface modification, and specifically relates to a composite treatment method in which the surface of a metal material is first coated and then nitrided, and is suitable for surface strengthening of cutting tools, molds and metal parts. First, magnetron sputtering or arc ion plating is used to deposit a layer of nitride film on the surface of the metal material substrate, the film thickness is 0.1-50 microns; then ion nitriding treatment is performed on the coating surface by ion nitriding technology, and the treatment time is 0.5-50 microns. 10 hours. Thus, it solves the problem of low bonding strength of the film base caused by the black layer that is easy to appear in the coating composite treatment process after nitriding first. By first depositing a thin film and then ion nitriding treatment, the coating-nitriding composite treatment method The obtained workpiece has the characteristics of high surface hardness, good wear resistance, high film-base bonding force, reliable and stable quality, etc.

Description

A kind of composite treatment method of coating first and then nitriding on the surface of metal material

Technical field:

The invention belongs to the field of material surface modification, and specifically relates to a composite treatment method in which the surface of a metal material is first coated and then nitrided, and is suitable for surface strengthening of cutting tools, molds and metal parts.

Background technique:

As a thermochemical treatment process, nitriding treatment can generally improve the fatigue resistance, wear resistance and corrosion resistance of steel. However, the surface hardness of the workpiece after nitriding treatment is still low, which still cannot meet the growing demands of harsh application conditions.

Hard coatings such as TiN prepared by physical vapor deposition (Physical Vapor Deposition, PVD) have become the most widely used surface coatings. Due to the advantages of high hardness, high adhesion strength, low friction coefficient and good chemical stability, TiN coating has been widely used in various fields, especially the tool industry. With the increasingly harsh application conditions, TiN-based hard coatings can no longer meet the surface requirements of tools, molds and some important workpieces. The main reason is that the mold steel substrate is soft, or the bonding force between the coating and the substrate is not enough. Therefore, relying solely on a certain treatment technology can no longer meet the requirements of high fatigue strength, high bending strength, high red hardness, low friction and wear, and high-speed and heavy load.

In order to solve the deficiency of single treatment technology, Finnish scientist Korhnen et al. [A.S.Korhonen, E.H.Sirvio, M.S.Sulonen. Combining bulk nitriding and physical vapor deposition processes, a new technology of plasma nitriding (Plasma Nitriding, PN)/physical vapor deposition (PVD) composite treatment (PN/PVD) has been developed. The reason why the durability of the composite treatment layer is improved is that the nitriding layer increases the hardness of the substrate to increase its bearing capacity, which not only gives strong support to the hard and brittle coating, but also reduces the hardness gradient of the film/substrate interface. The relatively smooth hardness gradient reduces the stress in the coating and makes the stress distribution at the interface more uniform under load, so the possibility of brittle coating damage or cracking is reduced and the durability is improved.

Due to the incomparable advantages of this composite treatment technology, it has been extensively studied and paid attention to since the 1990s, and a lot of research has been done on its deposition equipment development, treatment process, workpiece structure and related properties after treatment. Moreover, the types of materials treated by PN/PVD composite treatment have developed from the initial carbon steel to low-alloy steel, stainless steel, die steel, aluminum and aluminum alloys, titanium and titanium alloys, and even cast iron. With the continuous development of composite treatment technology, composite treatment The types of materials will continue to expand. For example:

Wang Liping of Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences [Wang Liping, Xue Qunji, Zhang Guangan. Preparation method of diamond-like composite coating on piston ring surface. Invention patent: 200810150858.0] discloses a preparation method of diamond-like composite coating on piston ring surface. Methods A nitrided layer was formed on the surface of the piston ring by low-temperature plasma nitriding treatment, and then a hydrogen-free diamond-like film was deposited by magnetic filter cathodic arc-magnetron sputtering to improve the wear resistance and self-lubrication of the piston ring performance.

Guo Qiuyan et al [Guo Qiuyan, Liu Guangyu, Li Li, Liu Qiang, Yang Anzhi, Zhao Fuquan. Invention patent: 201210194611.5] from Zhejiang Geely Automobile Research Institute Co., Ltd. disclose a surface composite treatment method for steel molds. After the heat treatment, the steel mold is first sprayed with tiles, and then an ion nitriding layer is formed on the surface of the mold by ion nitriding, and finally ion coating is performed on the surface of the mold. The steel mold treated by the method improves its surface hardness, wear resistance and film-base bonding strength, and solves the technical problem that the surface of the traditional mold is easily damaged in the early stage of reuse.

Ma Shengli and Xu Ke of Xi'an Jiaotong University [Ma Shengli, Xu Ke. Precision blade hot forging die PCVD plasma infiltration composite strengthening method. Invention patent: 02114481.8] disclosed a precision blade hot forging die PCVD plasma infiltration Plating compound strengthening method, this method puts the blade mold after quenching and tempering into an industrial PCVD vacuum furnace for plasma nitriding, and then uses PCVD to deposit TiN or TiCN film. The mold processed by the method has improved surface hardness and film-base bonding strength, and is suitable for more severe friction and wear conditions.

Although the nitriding-coating composite treatment solves the shortcomings of single nitriding and single coating process, the composite treatment layer has higher hardness, substrate bearing capacity and wear resistance, but if the process is not applied properly, it is easy to appear a black layer, black The formation of the layer is due to the outward diffusion of nitrogen in the nitride Fe ₄ N and Fe _2-3 N in the outer layer of the nitride layer during the ion plating process, thereby transforming into ferrite. The ferrite layer not only has very low hardness, but also has a certain degree of looseness, which will greatly reduce the film-base bonding strength of the composite treatment layer, and seriously affect the friction and wear performance and service life of the composite treatment layer.

Invention content:

In order to solve the above problems, the object of the present invention is to provide a composite treatment method in which the surface of the metal material is first coated and then nitrided. Long life and other advantages, so as to better improve the performance of metal workpieces.

Technical scheme of the present invention is:

The invention relates to a compound treatment method of coating the surface of a metal material and then nitriding. The vacuum coating method is used to deposit a layer of nitride thin film on the surface of the metal material, and then ion nitriding treatment is performed after the thin film is deposited.

The composite treatment method of first coating the surface of the metal material and then nitriding, the vacuum coating method is magnetron sputtering or arc ion plating.

In the composite treatment method of coating the surface of the metal material and then nitriding, the nitride film is titanium nitride, chromium nitride, zirconium nitride, titanium aluminum nitride, chromium silicon nitride, titanium aluminum silicon nitride or nitride Chromium-aluminum thin film, the thickness of the film is 0.1-50 microns.

In the composite treatment method of first coating the surface of the metal material and then nitriding, the ion nitriding treatment is arc ion nitriding and/or glow ion nitriding.

In the composite treatment method of first coating the surface of the metal material and then nitriding, when the ion nitriding treatment is arc ion nitriding treatment, the arc ion source is installed in the magnetron sputtering or arc ion plating equipment.

The composite treatment method in which the surface of the metal material is first coated and then nitrided comprises the following steps:

(1) Workpiece pre-treatment: After degreasing, anhydrous alcohol ultrasonic cleaning and drying, the workpiece to be treated is placed on the sample stage in the magnetron sputtering or arc ion plating equipment;

(2) Vacuuming and workpiece preheating: Start the vacuuming system of the magnetron sputtering or arc ion plating equipment, and when the vacuum degree of the vacuum chamber reaches 1×10 ^-2 Pa～5×10 ^-3 Pa, turn on the heater to The workpiece in the vacuum chamber is heated to 20-550°C;

(3) Glow cleaning: Introduce argon gas into the vacuum chamber, control the air pressure between 0.5 and 2Pa, turn on the bias power supply, and control the bias voltage in the range of -400V to -1000V, so that the gas will undergo glow discharge, and the surface of the workpiece will be damaged. Perform glow cleaning for 5-60 minutes;

When using the arc ion plating technology, after the glow cleaning, it is necessary to open the cathode arc target for arc light ion bombardment cleaning, the workpiece bias is controlled at -500~-1000V, and the workpiece is bombarded and cleaned for 1 to 10 minutes;

(4) Deposit thin film transition layer: Introduce argon gas into the vacuum chamber, control the air pressure between 0.1 and 2Pa, and turn on the target power supply in magnetron sputtering or arc ion plating at the same time, and control the bias voltage of the workpiece at -100～- 600V, first deposit a transition layer of 100-500nm, and the deposition time is 1-30 minutes;

(5) Thin film deposition: Introduce nitrogen gas into the vacuum chamber, control the air pressure between 0.1 and 2Pa, control the bias voltage of the workpiece at -50 to -1500V, turn on the magnetron or arc cathode target, and deposit the nitride film. The film deposition time is 20 to 300 minutes; after the deposition is over, quickly turn off the power switch of the target;

(6) Nitriding treatment: Use arc light ion nitriding and/or glow ion nitriding technology for ion nitriding treatment.

In the composite treatment method of first coating and then nitriding the surface of the metal material, the nitriding treatment process is carried out on the surface of the workpiece after the film is deposited by using the arc light ion nitriding technology:

When the temperature of the workpiece is controlled at 300-650°C, the nitrogen pressure is adjusted to be between 0.1-1Pa, the bias voltage of the workpiece is controlled at -400--1500V, and the power supply of the arc ion source heating wire is turned on. The heating wire generates thermal electron emission and hits the cathode The nitrogen molecules in the cylinder make it form nitrogen ions N ⁺ ; then turn on the arc discharge power supply, and apply a 80-100V DC power supply between the cathode cylinder and the vacuum chamber wall, thereby generating arc discharge in the cathode cylinder to form arc nitrogen plasma Under the action of the focus of the focusing magnetic field and the plasma arc voltage, it accelerates into the vacuum chamber and starts nitriding treatment on the surface of the workpiece. The treatment time is 30 to 300 minutes; after the nitriding is completed, quickly turn off the arc ion source arc discharge Power supply, hot wire power supply and focusing magnetic field power supply, turn off the bias power supply of the workpiece, stop the gas supply, continue to vacuum, the workpiece is cooled to below 50°C with the furnace, and the coating-nitriding composite treatment process is over.

In the composite treatment method of first coating and then nitriding the metal material surface, the nitriding treatment process is carried out on the surface of the workpiece after the film is deposited by using the glow ion nitriding technology:

After the deposited film is ultrasonically cleaned with anhydrous alcohol, put it into the ion nitriding furnace, and when the vacuum reaches 5×10 ^-3 Pa ~ 1×10 ^-2 Pa, turn on the heater to heat the workpiece in the nitriding furnace to 400-550°C; Ammonia gas is introduced into the nitriding furnace, the air pressure is controlled at 100-1000Pa, and a DC power supply of 400-800V is applied between the anode nitriding furnace wall and the cathode workpiece, and a glow is generated between the anode and cathode. Nitrogen plasma is formed by photodischarge, and nitrogen ions are accelerated to the surface of the workpiece for nitriding treatment under the action of the bias electric field of the workpiece. The treatment time is 0.5 to 40 hours; In, the vacuum is continued, the workpiece is cooled to below 50°C with the furnace, and the nitriding process is over.

Core idea of the present invention is:

Utilizing the thermodynamic imbalance of magnetron sputtering or arc ion plating technology in film deposition, the deposited film has more defects and the stoichiometric ratio cannot fully reach the ideal ratio, and then ion nitriding is carried out, and nitrogen ions pass through the film These defect positions or other gap positions in the film are thermally diffused directly to the film-base interface. Furthermore, the diffusion into the surface layer of the workpiece is 5-200 microns, which not only improves the bonding strength of the film base, but also improves the hardness and wear resistance of the film layer.

The beneficial effects of the present invention are:

1. The present invention first adopts magnetron sputtering and/or arc ion plating on the surface of the metal material, deposits a layer of nitride film with a thickness of 0.1 to 50 microns on the surface of the metal material, and then undergoes arc ion nitriding and/or Composite treatment method of glow ion nitriding. The invention utilizes the premise of small film grain size and high defect density caused by the non-equilibrium of magnetron sputtering or arc ion plating technology in the film deposition process, and performs ion nitriding on the film surface after film deposition, which can effectively Reduce film defect density and improve film compactness.

2. In the present invention, ion nitriding is carried out after ion coating on the surface of the metal workpiece, nitrogen ions diffuse on the surface of the film and the substrate workpiece to form a nitrogen gradient, and it is not easy to form ferrite in the process of "nitriding/coating composite treatment" layer, effectively ensuring the film-base bonding strength of the composite treatment layer.

3. The present invention solves the problem of low bonding strength of the film base caused by the black layer that is easy to appear in the process of nitriding first and then the coating composite treatment process. Compared with the conventional nitriding/coating composite treatment process, the coating/nitriding composite treatment process It is easier to control, the bonding strength of the film base and the density of the film are higher, which can effectively improve the surface hardness, wear resistance and service life of metal workpieces.

Detailed ways:

The present invention will be further described in detail below in conjunction with specific embodiments.

Example 1

(1) Workpiece pre-treatment: The workpiece is made of high-speed steel (grade W18Cr4V), the size of the workpiece is 20mm×10mm×10mm, and the size of the treated surface is 20mm×10mm. After degreasing, anhydrous alcohol ultrasonic cleaning and drying, the workpiece to be treated is placed on the sample stage in the ion nitriding/arc ion plating composite treatment equipment;

(2) Vacuuming and workpiece preheating: start the vacuuming system of the composite processing equipment, and when the vacuum degree of the vacuum chamber reaches 5×10 ^-3 Pa, turn on the heater to heat the workpiece in the vacuum chamber to 400°C;

(3) Glow (or/and arc) cleaning: Introduce argon gas into the vacuum chamber, control the air pressure at 2.0Pa, turn on the bias power supply, and control the bias voltage at -800V, so that the gas will glow discharge, and the surface of the workpiece will be cleaned. Glow cleaning for 20 minutes; then adjust the argon gas pressure to 0.8Pa, turn on the cathodic arc pure titanium target, the target current is 80A, perform arc ion bombardment cleaning, control the bias voltage of the workpiece at -1000V, and bombard and clean the workpiece for 5 minutes;

(4) Deposit thin film transition layer: the argon gas pressure is maintained at 0.8Pa, the workpiece bias is adjusted to -600V, the pure titanium transition layer is deposited first, the deposition time is 3 minutes, and the thickness of the pure titanium transition layer is 150nm;

(5) Thin film deposition: Nitrogen gas is introduced into the vacuum chamber, the air pressure is controlled at 0.8Pa, the workpiece bias is controlled at -500V, the cathodic arc pure titanium target current is still maintained at 80A, and the TiN film is deposited. The film deposition time is 60 minutes; After the deposition is over, quickly turn off the target power switch;

(6) Nitriding treatment: When the temperature of the workpiece is controlled at 450°C, the nitrogen pressure is adjusted to 0.6Pa, the bias voltage of the workpiece is controlled at -800V, the focusing magnetic field power supply is turned on, the current is set to 0.5A, and the arc ion source heating wire power supply is turned on. The current of the hot wire is adjusted to 100A, and the hot wire generates thermal electron emission, which hits the nitrogen molecules in the cathode cylinder to form nitrogen ions N ⁺ ; then turns on the arc discharge power supply, and applies a 80-100V voltage between the cathode cylinder and the vacuum chamber wall. DC power supply, so that an arc discharge is generated in the cathode cylinder to form an arc nitrogen plasma. Under the focusing of the focusing magnetic field and the action of the plasma arc voltage, it accelerates into the vacuum chamber and begins to nitriding the workpiece surface. The processing time is 60 minutes; after the nitriding is finished, quickly turn off the arc discharge power supply, hot wire power supply and focusing magnetic field power supply of the arc ion source, turn off the bias power supply of the workpiece, stop the gas supply, and continue to vacuum, the workpiece is cooled to below 50 ° C with the furnace, and the coating - End of nitriding complex process.

After the workpiece is taken out, the treated surface of the sample is cut and bonded, polished and corroded with 4wt% nitric acid alcohol solution. The thickness of the TiN film is measured to be 3.2 microns, and the thickness of the nitrided layer in high-speed steel is about 6 microns. Then, the surface microhardness and film-substrate bonding strength of the composite treatment layer were tested with a microhardness tester and a scratch tester, which were 26GPa and 75N, respectively.

Example 2

(1) Workpiece pre-treatment: The workpiece is made of high-speed steel (grade W6Mo5Cr4V2Al), the size of the workpiece is 20mm×10mm×10mm, and the size of the treated surface is 20mm×10mm. After degreasing, anhydrous alcohol ultrasonic cleaning and drying, the workpiece to be treated is placed on the sample stage in the ion nitriding/arc ion plating composite treatment equipment;

(2) Vacuuming and workpiece preheating: start the vacuuming system of the composite processing equipment, and when the vacuum degree of the vacuum chamber reaches 6×10 ^-3 Pa, turn on the heater to heat the workpiece in the vacuum chamber to 430°C;

(3) Glow (or/and arc) cleaning: Introduce argon gas into the vacuum chamber, control the air pressure at 1.5Pa, turn on the bias power supply, and control the bias voltage at -750V, so that the gas will glow discharge, and the surface of the workpiece will be cleaned. Glow cleaning for 20 minutes; then adjust the argon gas pressure to 0.8Pa, turn on the cathodic arc high-purity titanium-aluminum alloy (titanium-aluminum weight ratio is 7:3) target, the target current is 75A, perform arc ion bombardment cleaning, and workpiece bias control At -1000V, bombard and clean the workpiece for 5 minutes;

(4) Deposit thin film transition layer: maintain the argon gas pressure at 0.8Pa, adjust the workpiece bias to -600V, first deposit the titanium-aluminum transition layer, the deposition time is 5 minutes, and the thickness of the titanium-aluminum transition layer is 250nm;

(5) Thin film deposition: Nitrogen gas is introduced into the vacuum chamber, the air pressure is controlled at 0.8Pa, the workpiece bias is controlled at -500V, the cathodic arc titanium aluminum alloy target current is still maintained at 80A, and the TiAlN film is deposited, and the film deposition time is 60 minutes; After the deposition is over, quickly turn off the target power switch;

(6) Nitriding treatment: When the temperature of the workpiece is controlled at 450°C, the nitrogen pressure is adjusted to 0.6Pa, the bias voltage of the workpiece is controlled at -800V, the focusing magnetic field power supply is turned on, the current is set to 0.5A, and the arc ion source heating wire power supply is turned on. The current of the hot wire is adjusted to 100, and the hot wire generates thermal electron emission, which hits the nitrogen molecules in the cathode cylinder to form nitrogen ions N ⁺ ; then turns on the arc discharge power supply, and applies a 80-100V voltage between the cathode cylinder and the vacuum chamber wall. DC power supply, so that an arc discharge is generated in the cathode cylinder to form an arc nitrogen plasma. Under the focusing of the focusing magnetic field and the action of the plasma arc voltage, it accelerates into the vacuum chamber and begins to nitriding the workpiece surface. The processing time is 40 minutes; after the nitriding is finished, quickly turn off the arc discharge power supply, hot wire power supply and focusing magnetic field power supply of the arc ion source, turn off the bias power supply of the workpiece, stop the gas supply, continue to vacuum, the workpiece is cooled to below 50°C with the furnace, and then coated - End of nitriding complex process.

After the workpiece was taken out, the treated surface of the sample was cut open, bonded, polished and corroded with 4wt% nitric acid alcohol solution. The thickness of the TiAlN film was measured to be 3.6 microns, and the thickness of the nitrided layer in high-speed steel was about 4 microns. Then, the surface microhardness and film-substrate bonding strength of the composite treatment layer were tested with a microhardness tester and a scratch tester, which were 32GPa and 72N, respectively.

Example 3

(1) Workpiece pretreatment: The workpiece is made of austenitic stainless steel (grade 0Cr19Ni9), the size of the workpiece is Φ30mm×10mm, and the size of the treated surface is Φ30mm×10mm. After degreasing, anhydrous alcohol ultrasonic cleaning and drying, the workpiece to be treated is placed on the sample stage in the ion nitriding/magnetron sputtering composite processing equipment;

(2) Vacuuming and workpiece preheating: start the vacuuming system of the composite processing equipment, and when the vacuum degree of the vacuum chamber reaches 5×10 ^-3 Pa, turn on the heater to heat the workpiece in the vacuum chamber to 400°C;

(3) Glow cleaning: Introduce argon gas into the vacuum chamber, control the air pressure at 2.0Pa, turn on the bias power supply, and control the bias voltage at -800V to make the gas glow discharge, and perform glow cleaning on the surface of the workpiece for 20 minutes;

(4) Deposit thin film transition layer: the argon gas pressure is maintained at 2.0Pa, the workpiece bias is adjusted to -600V, the pure titanium transition layer is deposited first, the deposition time is 3 minutes, and the thickness of the pure titanium transition layer is 180nm;

(5) Thin film deposition: Introduce nitrogen gas into the vacuum chamber, control the air pressure at 0.8Pa, control the bias voltage of the workpiece at -500V, and maintain the magnetron target current at 10A, deposit the TiN film, and the film deposition time is 120 minutes; after the deposition is completed , quickly turn off the power switch of the magnetron target;

(6) Nitriding treatment: When the temperature of the workpiece is controlled at 450°C, the nitrogen pressure is adjusted to 0.6Pa, the bias voltage of the workpiece is controlled at -800V, the focusing magnetic field power supply is turned on, the current is set to 0.5A, and the arc ion source heating wire power supply is turned on. The current of the hot wire is adjusted to 100A, and the hot wire generates thermal electron emission, which hits the nitrogen molecules in the cathode cylinder to form nitrogen ions N ⁺ ; then turns on the arc discharge power supply, and applies a 80-100V voltage between the cathode cylinder and the vacuum chamber wall. DC power supply, so that an arc discharge is generated in the cathode cylinder to form an arc nitrogen plasma. Under the focusing of the focusing magnetic field and the action of the plasma arc voltage, it accelerates into the vacuum chamber and begins to nitriding the workpiece surface. The processing time is 60 minutes; after the nitriding is finished, quickly turn off the arc discharge power supply, hot wire power supply and focusing magnetic field power supply of the arc ion source, turn off the bias power supply of the workpiece, stop the gas supply, and continue to vacuum, the workpiece is cooled to below 50 ° C with the furnace, and the coating - End of nitriding complex process.

After the workpiece is taken out, the treated surface of the sample is cut and bonded, polished and corroded with a 4wt% nitric acid alcohol solution. The thickness of the TiN film is measured to be 2.2 microns, and the thickness of the nitrided layer in stainless steel is 2 microns. Then, the surface microhardness and film-substrate bonding strength of the composite treatment layer were tested with a microhardness tester and a scratch tester, which were 24GPa and 80N, respectively.

Example 4

(1) Workpiece pre-treatment: The workpiece is made of high-speed steel (grade W18Cr4V), the size of the workpiece is 20mm×10mm×10mm, and the size of the treated surface is 20mm×10mm. After degreasing, anhydrous alcohol ultrasonic cleaning and drying, the workpiece to be treated is placed on the sample stage in the arc ion plating equipment;

(2) Vacuuming and workpiece preheating: start the vacuuming system of the arc ion plating equipment, and when the vacuum degree of the vacuum chamber reaches 5×10 ^-3 Pa, turn on the heater to heat the workpiece in the vacuum chamber to 400°C;

(3) Glow (or/and arc) cleaning: Introduce argon gas into the vacuum chamber, control the air pressure at 2.0Pa, turn on the bias power supply, and control the bias voltage at -800V, so that the gas will glow discharge, and the surface of the workpiece will be cleaned. Glow cleaning for 20 minutes; then adjust the argon gas pressure to 0.8Pa, turn on the cathodic arc pure titanium target, the target current is 80A, perform arc ion bombardment cleaning, control the bias voltage of the workpiece at -1000V, and bombard and clean the workpiece for 5 minutes;

(4) Deposit thin film transition layer: maintain the argon gas pressure at 0.8Pa, adjust the workpiece bias to -600V, first deposit the pure titanium transition layer, the deposition time is 3 minutes, and the thickness of the pure titanium transition layer is 150nm;

(5) Thin film deposition: Nitrogen gas is introduced into the vacuum chamber, the air pressure is controlled at 0.8Pa, the workpiece bias is controlled at -500V, the cathodic arc pure titanium target current is still maintained at 80A, and the TiN film is deposited. The film deposition time is 60 minutes; After the deposition is completed, quickly turn off the power switch of the target, turn off the bias power of the workpiece, stop the gas supply, continue to vacuum, and take out the sample when the workpiece is cooled to below 50°C with the furnace;

(6) Nitriding treatment: ultrasonically clean and dry the coated workpiece, place it on the sample stage of the glow ion nitriding furnace, and when vacuuming to 7×10 ^-3 Pa, turn on the heater and heat the workpiece to 550°C; then feed ammonia gas into the nitriding furnace with a pressure of 500Pa, apply a DC power supply of 800V between the anode nitriding furnace wall and the cathode workpiece, and then generate glow discharge between the cathode and anode to form nitrogen plasma , a glow discharge is generated between the workpiece and the nitriding furnace wall, and the nitriding treatment on the surface of the workpiece is started, and the treatment time is 300 minutes; after the nitriding is completed, the bias power supply of the workpiece is quickly turned off, the gas supply is stopped, and the vacuum is continued , the workpiece is cooled to below 50°C with the furnace, and the nitriding process is over.

After the workpiece is taken out, the treated surface of the sample is cut and bonded, polished and corroded with a 4wt% nitric acid alcohol solution. The thickness of the TiN film is measured to be 3.1 microns, and the thickness of the nitrided layer in high-speed steel is 10 microns. Then, the surface microhardness and film-substrate bonding strength of the composite treatment layer were tested with a microhardness tester and a scratch tester, which were 24GPa and 72N, respectively.

The results of the examples show that the present invention first deposits a layer of nitride film on the surface of the metal material substrate by magnetron sputtering or arc ion plating, and the film thickness is 0.1 to 50 microns; then ion nitriding is carried out on the coating surface by using ion nitriding technology Treatment, the treatment time is 0.5 to 10 hours. The workpiece obtained by the method of the invention has the characteristics of high surface hardness, good wear resistance, high film-base binding force, reliable and stable quality, and the like.

Claims (8)

1. A composite treatment method for first coating and then nitriding on the surface of a metal material, characterized in that, the vacuum coating method is used to deposit a layer of nitride film on the surface of the metal material, and then process through ion nitriding after the deposited film. 2. according to the composite treatment method of first film coating and then nitriding of metal material surface according to claim 1, it is characterized in that, vacuum coating method is magnetron sputtering or arc ion plating method. 3. according to claim 1, the composite treatment method of coating and then nitriding on the metal material surface is characterized in that, the nitride film is titanium nitride, chromium nitride, zirconium nitride, titanium aluminum nitride, chromium nitride Silicon, titanium aluminum silicon nitride or chromium aluminum nitride film, the thickness of the film is 0.1-50 microns. 4. The composite treatment method of first coating and then nitriding the metal material surface according to claim 1, wherein the ion nitriding treatment is an arc ion nitriding or glow ion nitriding method. 5. according to the composite treatment method of first film coating and then nitriding of metal material surface according to claim 4, it is characterized in that, when ion nitriding treatment is arc light ion nitriding treatment, arc light ion source is installed in magnetron sputtering or electric arc in ion plating equipment. 6. According to the composite treatment method of coating and then nitriding the metal material surface according to one of claims 1 to 5, it is characterized in that it comprises the following steps: (1) Workpiece pre-treatment: After degreasing, anhydrous alcohol ultrasonic cleaning and drying, the workpiece to be treated is placed on the sample stage in the magnetron sputtering or arc ion plating equipment; (2) Vacuuming and workpiece preheating: Start the vacuuming system of the magnetron sputtering or arc ion plating equipment, and when the vacuum degree of the vacuum chamber reaches 1×10 ^-2 Pa～5×10 ^-3 Pa, turn on the heater to The workpiece in the vacuum chamber is heated to 20-550°C; (3) Glow cleaning: Introduce argon gas into the vacuum chamber, control the air pressure between 0.5 and 2Pa, turn on the bias power supply, and control the bias voltage in the range of -400V to -1000V, so that the gas will undergo glow discharge, and the surface of the workpiece will be damaged. Perform glow cleaning for 5-60 minutes; When using the arc ion plating technology, after the glow cleaning, it is necessary to open the cathode arc target for arc light ion bombardment cleaning, the workpiece bias is controlled at -500~-1000V, and the workpiece is bombarded and cleaned for 1 to 10 minutes; (4) Deposit thin film transition layer: Introduce argon gas into the vacuum chamber, control the air pressure between 0.1 and 2Pa, and turn on the target power supply in magnetron sputtering or arc ion plating at the same time, and control the bias voltage of the workpiece at -100～- 600V, first deposit a transition layer of 100-500nm, and the deposition time is 1-30 minutes; (5) Thin film deposition: Introduce nitrogen gas into the vacuum chamber, control the air pressure between 0.1 and 2Pa, control the bias voltage of the workpiece at -50 to -1500V, turn on the magnetron or arc cathode target, and deposit the nitride film. The film deposition time is 20 to 300 minutes; after the deposition is over, quickly turn off the power switch of the target; (6) Nitriding treatment: Use arc light ion nitriding or glow ion nitriding technology for ion nitriding treatment. 7. according to the composite treatment method of first coating and then nitriding of the metal material surface according to claim 6, it is characterized in that, adopting the arc light ion nitriding technology to carry out the nitriding treatment process to the workpiece surface after the deposited film is: When the temperature of the workpiece is controlled at 300-650°C, the nitrogen pressure is adjusted to be between 0.1-1Pa, the bias voltage of the workpiece is controlled at -400--1500V, and the power supply of the arc ion source heating wire is turned on. The heating wire generates thermal electron emission and hits the cathode The nitrogen molecules in the cylinder make it form nitrogen ions N ⁺ ; then turn on the arc discharge power supply, and apply a 80-100V DC power supply between the cathode cylinder and the vacuum chamber wall, thereby generating arc discharge in the cathode cylinder to form arc nitrogen plasma Under the action of the focus of the focusing magnetic field and the plasma arc voltage, it accelerates into the vacuum chamber and starts nitriding treatment on the surface of the workpiece. The treatment time is 30 to 300 minutes; after the nitriding is completed, quickly turn off the arc ion source arc discharge Power supply, hot wire power supply and focusing magnetic field power supply, turn off the bias power supply of the workpiece, stop the gas supply, continue to vacuum, the workpiece is cooled to below 50°C with the furnace, and the coating-nitriding composite treatment process is over. 8. according to the composite treatment method of first film-coating and then nitriding of the metal material surface according to claim 6, it is characterized in that, adopting the glow ion nitriding technology to carry out the nitriding treatment process on the workpiece surface after the deposited film is: After the deposited film is ultrasonically cleaned with anhydrous alcohol, put it into the ion nitriding furnace, and when the vacuum reaches 5×10 ^-3 Pa ~ 1×10 ^-2 Pa, turn on the heater to heat the workpiece in the nitriding furnace to 400-550°C; Ammonia gas is introduced into the nitriding furnace, the air pressure is controlled at 100-1000Pa, and a DC power supply of 400-800V is applied between the anode nitriding furnace wall and the cathode workpiece, and a glow is generated between the anode and cathode. Nitrogen plasma is formed by photodischarge, and nitrogen ions are accelerated to the surface of the workpiece for nitriding treatment under the action of the bias electric field of the workpiece. The treatment time is 0.5 to 40 hours; In, the vacuum is continued, the workpiece is cooled to below 50°C with the furnace, and the nitriding process is over.