Vacuum coating method for multi-layer composite metal coating on surface of alloy base material and application of vacuum coating method

Abstract

The invention discloses a vacuum coating method for a multi-layer composite metal coating on the surface of an alloy base material and application of the vacuum coating method, and relates to the technical field of vacuum coating. According to the method, through the multi-step synergistic effect of electron beam enhanced plasma cleaning, metal ion bombardment, gradient metal deposition and heat treatment, a compact tantalum or niobium / zirconium niobium alloy / zirconium niobium oxidation multilayer coating with high binding force is formed on the surface of an alloy base material. The hardness of the coating can reach 655-1000 HV, and the coating can resist 600 DEG C thermal shock circulation for 50 times without cracks. The method is particularly suitable for surface strengthening of medical implants in the orthopedics department, the dentistry department and the like, and the wear resistance and the biological safety of the medical implants are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum coating, and particularly relates to a vacuum coating method for preparing a multilayer composite metal coating with high hardness, excellent thermal shock resistance and bonding strength on the surface of an alloy substrate, and application of the method to the surface of a medical implant material. BACKGROUND

[0002] Titanium alloy and cobalt-chromium-molybdenum alloy and other alloy substrates have been widely used in the medical implant field (such as artificial joints, orthopedic internal fixation implants, dental implants, etc.) due to their excellent mechanical properties (such as high specific strength), good corrosion resistance and biocompatibility. Compared with traditional medical metal materials such as stainless steel, alloy substrates can effectively reduce the rejection reaction of the body after implantation and reduce the risk of corrosion degradation during long-term use, and have become one of the preferred materials for medical implants. However, in actual clinical applications, the surface performance of pure titanium or conventional alloy substrates (such as Ti-6Al-4V) still has obvious defects and cannot fully meet the needs of complex physiological environments. On the one hand, the oxide film (mainly composed of TiO2) naturally formed on the surface of titanium and titanium alloy is relatively thin (usually only a few nanometers to tens of nanometers) and has a loose structure, which is easily worn and peeled off under long-term stress friction (such as the joint surface of artificial joints) or body fluid erosion, which not only reduces the service life of the implant, but also the peeled-off oxide particles can cause inflammation of the body, so titanium and titanium alloy cannot be used as joint surface materials for artificial joints. On the other hand, cobalt-chromium-molybdenum alloy, as a commonly used joint surface material for artificial joints, forms a joint surface with ultra-high molecular weight polyethylene or modified ultra-high molecular weight polyethylene. The joint surface wear rate of metal on polyethylene is five to ten times that of ceramic on polyethylene, resulting in much lower durability of metal on polyethylene joint surface than that of ceramic on polyethylene joint surface.

[0003] To solve the above problems, the prior art prepares a functional coating on the surface of the alloy substrate to improve its wear resistance, bioactivity and interface bonding performance. The commonly used coating preparation techniques at present mainly include chemical vapor deposition (CVD), thermal spraying (such as plasma spraying, flame spraying), sol-gel method and physical vapor deposition (PVD), etc., and the prepared coating materials cover hydroxyapatite (HA), zirconium oxide (ZrO2), pure tantalum (Ta), niobium (Nb) and various alloys, etc. At the same time, in the field of medical implant coating, the thickness, composition uniformity and biological safety of the coating are extremely strict: a coating that is too thick (such as more than 50 μm) will change the overall mechanical properties (such as elastic modulus) of the implant, which may cause "stress shielding effect" and affect the normal growth of bone tissue; and composition deviation (such as the Nb content in zirconium-niobium alloy deviating from the optimal range) will significantly reduce the biocompatibility and even cause toxic reactions in the body. In the prior art, some coating preparation methods (such as thermal spraying) are difficult to accurately control the thickness and composition uniformity of the coating, especially for implants with complex shapes (such as the thread structure of dental implants), which are prone to local over-thickness or coating omission; another technology can control the thickness, but the oxidation layer formation method of the coating is not optimized, resulting in poor bonding between the oxidation layer and the alloy layer, or uneven composition of the oxidation layer, which cannot effectively play the role of the coating.

[0004] In the prior art, physical vapor deposition (PVD) is used for surface modification of alloy substrates, but the traditional PVD technology has problems such as poor coating coverage uniformity, weak bonding force, and easy generation of microcracks. Especially for implants with porous structure or complex shape, the coating has poor coverage on the non-line-of-sight surface. Single coating structure also cannot meet the requirements of hardness, toughness and heat shock resistance at the same time.

[0005] In addition, the alloy substrate has the risk of ion precipitation in the human body environment, especially during long-term implantation, which may cause tissue reactions. At the same time, the insufficient hardness and wear resistance of the alloy substrate surface also limit its application in load-bearing implants, especially in the application of artifical joint surface materials. SUMMARY

[0006] OBJECTIVE

[0007] The purpose of the present application is to provide a vacuum plating method for a multilayer composite metal coating on the surface of an alloy substrate. The purpose of the present application is to solve the problems of weak bonding force, uneven performance, poor thermal stability, poor heat shock resistance and easy generation of microcracks of the coating on the surface of the alloy substrate.

[0008] TECHNICAL SCHEME

[0009] To achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0010] The application provides a vacuum plating method for a multilayer composite metal coating on the surface of an alloy substrate, comprising the following steps:

[0011] S1: polishing the alloy substrate, and cleaning the surface of the alloy substrate by means of argon ion electron beam enhanced plasma bombardment;

[0012] S2: forming a transition layer on the surface of the alloy substrate by means of metal electron beam enhanced plasma generated by arc discharge;

[0013] S3: performing first deposition by means of physical vapor deposition (PVD), and taking tantalum or niobium as target material of the metal film layer;

[0014] S4: performing second deposition of the zirconium-niobium alloy layer by means of the same method, and taking Zr 97.5 Nb 2.5 (wt%) zirconium-niobium alloy as target material of the metal film layer;

[0015] forming a composite coating through two times of metal deposition;

[0016] S5: performing heat treatment on the coating to form a zirconium-niobium oxide layer.

[0017] The alloy substrate is a titanium alloy substrate or a cobalt-chromium-molybdenum alloy substrate.

[0018] The parameters of the electron beam enhanced plasma cleaning are as follows: vacuum degree 1 Pa, negative bias voltage 150-250 V, arc current 150-200 A, and time 60-120 min.

[0019] The parameters of the metal ion bombardment are as follows: vacuum degree 0.1 Pa, negative bias voltage 300-500 V, magnetron sputtering current 20-40 A, and time 200-400 min.

[0020] The parameters of the first metal deposition are as follows: vacuum degree 0.5 Pa, negative bias voltage 40-200 V, magnetron sputtering current 10-100 A, and time 5-10 h; and the parameters of the second metal deposition are as follows: vacuum degree 0.1 Pa, negative bias voltage 200-350 V, magnetron sputtering current 10-100 A, and time 30-40 h.

[0021] The heat treatment is performed at a temperature of 500-620 ℃ for 6-10 h.

[0022] The plating machine comprises an arc target and a plurality of magnetron targets, and the target materials include titanium, tantalum or niobium, and zirconium-niobium alloy.

[0023] The thickness of the pure tantalum or pure niobium layer is not less than 5 μm; and the zirconium-niobium alloy has a composition of Zr 97.5 Nb 2.5 (wt%), and the thickness is greater than 3 times the thickness of the tantalum or niobium layer.

[0024] The final alloy substrate surface multilayer composite metal coating comprises a tantalum or niobium layer with a thickness of 5-10 microns, a zirconium-niobium alloy layer with a thickness of 20-35 microns, and a zirconium-niobium oxide layer with a thickness of 3-10 microns.

[0025] An alloy substrate with a multilayer composite metal coating prepared on the surface thereof by the aforementioned plating method.

[0026] The heat treatment is carried out at 550-620℃ for 6-10h.

[0027] The plating machine comprises an arc target and at least three magnetron targets, and the target materials are titanium, tantalum or niobium, and zirconium-niobium alloy in sequence, and a magnetron power source is a high-frequency pulse power source.

[0028] A medical alloy substrate implant prepared by a vacuum plating method using a multilayer composite metal coating on the surface of an alloy substrate.

[0029] Working principle

[0030] The present application is prepared by polishing and cleaning a medical alloy substrate base material, ion bombardment activation, and then sequentially depositing a 5-10 micron tantalum / niobium layer, a 20-35 micron Zr97.5Nb2.5 alloy layer by PVD method, and then forming a 3-10 micron zirconium-niobium oxide layer by heat preservation at 500℃-620℃. The coating has strong adhesion, dense structure, can retain the performance of the base material, improve the hardness (650-1050HV) and thermal resistance, improve the biocompatibility, and enhance the bone bonding ability after implantation.

[0031] Advantages:

[0032] The high-performance coating on the surface of the alloy substrate designed in the present application has a multilayer structure, has strong adhesion to the substrate, dense structure, good biocompatibility, and the like, the surface hardness of the film layer can reach 650-1050HV, and has good wear resistance compared with the original alloy; after 50 times of cyclic heating-cooling thermal shock from room temperature to 600℃, no microcracks are observed on the surface of the coating. Specific embodiments

[0033] The application will be further described in detail below with specific examples. The examples are only a description of the embodiments of the application and do not have any limitation on the scope of the application. Although the preferred embodiments of the application are introduced below, it is clear that the application can be implemented in various forms and should not be limited to the embodiments described herein. For the cases not marked with specific techniques or conditions in the examples, the techniques and conditions recorded in the literature in the art can be used or the operation can be referred to the product manual. If the manufacturers of the reagents and instruments used in the implementation process are not specified, they are all conventional products that can be purchased in the market. In the following examples, unless otherwise specified, "%" represents the percentage by weight, and "parts" represents the weight parts.

[0034] The test standards used in the application are as follows:

[0035] The coating thickness test standard of the application: the film thickness of the sample is tested according to GB / T31563-2015 Metal Coating Thickness Measurement Scanning Electron Microscope Method.

[0036] Example 1

[0037] A φ120x25mm circular arc titanium target is installed in the arc target of the coating machine, a φ75x650mm cylindrical titanium target is installed in the magnetron target 1, a φ75x650mm cylindrical titanium target is installed in the magnetron target 2, a φ75x650mm cylindrical zirconium niobium target is installed in the magnetron target 3, and a high-frequency pulse power supply is used for the target magnetron power supply. The cleaned and dried alloy base material is placed in the vacuum coating machine, and the initial temperature is 31℃. When the vacuum degree reaches 0.004pa, the coating begins. The vacuum degree of the S1 electron beam enhanced plasma bombardment method process is 1pa, the cleaning time is 90min, the negative bias is 200V, the arc current is 180A, and the anode current is 80A. The vacuum degree of the S2 metal ion bombardment method process is 0.1pa, the bombardment time is 300min, the negative bias is 400V, and the magnetron sputtering current is 30A. The vacuum degree of the S3 metal deposition method process is 0.5pa, the negative bias is 40V, the magnetron sputtering current is 10A, and the time is 6h. The coating end temperature is 75℃. The vacuum degree of the S4 metal deposition method process is 0.1pa, the negative bias is 250V, the magnetron sputtering current is 10A, and the time is 35h. The coating end temperature is 75℃. The temperature of the S5 heat treatment method is 550℃ and the time is 8 hours.

[0038] After testing, the thickness of the zirconium niobium alloy layer is about 22μm, the thickness of the zirconium niobium (Zr-Nb-O) oxide layer is about 4μm, and the actual object after coating can be seen. The alloy base material surface has a dense metal coating, the coating surface hardness reaches 655HV, and after 50 times of cyclic heating-cooling thermal shock from room temperature to 600℃, no microcracks are found on the coating surface.

[0039] Example 2

[0040] The arc target in the coating machine is installed with a φ120x25mm circular arc titanium target, the magnetron target 1 is installed with a φ75x650mm cylindrical titanium target, the magnetron target 2 is installed with a φ75x650mm cylindrical tantalum or niobium target, the magnetron target 3 is installed with a φ75x650mm cylindrical zirconium niobium target, and the target magnetron power source adopts a high-frequency pulse power source. The cleaned and dried alloy base material is placed into the vacuum coating machine, and the initial temperature is 31℃. When the vacuum degree reaches 0.004pa, the coating begins. The vacuum degree in the process of the S1 electron beam enhanced plasma bombardment method is 1pa, the cleaning time is 90min, the negative bias is 200V, the arc current is 180A, and the anode current is 80A. The vacuum degree in the process of the S2 metal ion bombardment method is 0.1pa, the bombardment time is 300min, the negative bias is 400V, and the magnetron sputtering current is 30A. The vacuum degree in the process of the S3 metal deposition method is 0.5pa, the negative bias is 100V, the magnetron sputtering current is 80A, and the time is 8h. The coating end temperature is 75℃. The vacuum degree in the process of the S4 metal deposition method is 0.1pa, the negative bias is 250V, the magnetron sputtering current is 10A, and the time is 35h. The coating end temperature is 75℃. The temperature of the S5 heat treatment method is 550℃, and the time is 8 hours.

[0041] After testing, the thickness of the tantalum or niobium layer is about 8μm, the thickness of the zirconium niobium alloy layer is about 22μm, and the thickness of the zirconium niobium (Zr-Nb-O) oxide layer is about 4μm. After the coating is completed, it can be seen that the alloy base material surface has a dense metal coating, and the coating surface hardness reaches 890HV. After 50 times of cyclic heating-cooling thermal shock from room temperature to 600℃, no microcracks are observed on the coating surface.

[0042] Example 3:

[0043] The arc target in the coating machine is installed with a φ120x25mm circular arc titanium target, the magnetron target 1 is installed with a φ75x650mm cylindrical titanium target, the magnetron target 2 is installed with a φ75x650mm cylindrical tantalum or niobium target, the magnetron target 3 is installed with a φ75x650mm cylindrical zirconium niobium target, and the target magnetron power source adopts a high-frequency pulse power source. The cleaned and dried alloy base material is placed into the vacuum coating machine, and the initial temperature is 31℃. When the vacuum degree reaches 0.004pa, the coating begins. The vacuum degree in the process of the S1 electron beam enhanced plasma bombardment method is 1pa, the cleaning time is 90min, the negative bias is 200V, the arc current is 180A, and the anode current is 80A. The vacuum degree in the process of the S2 metal ion bombardment method is 0.1pa, the bombardment time is 300min, the negative bias is 400V, and the magnetron sputtering current is 30A. The vacuum degree in the process of the S3 metal deposition method is 0.5pa, the negative bias is 100V, the magnetron sputtering current is 80A, and the time is 8h. The coating end temperature is 75℃. The vacuum degree in the process of the S4 metal deposition method is 0.1pa, the negative bias is 250V, the magnetron sputtering current is 10A, and the time is 35h. The coating end temperature is 75℃. The temperature of the S5 heat treatment method is 550℃, and the time is 8 hours.

[0044] The thickness of the tantalum or niobium layer is about 9 μm, the thickness of the zirconium-niobium alloy layer is about 22 μm, and the thickness of the zirconium-niobium (Zr-Nb-O) oxide layer is about 4 μm. After the coating is finished, the actual object can be seen to have a dense metal coating on the surface of the alloy base material. The surface hardness of the coating is 1000 HV. After 50 cycles of heating-cooling thermal shock from room temperature to 600°C, no microcracks are found on the surface of the coating.

[0045] Example 4:

[0046] A φ120x25mm circular arc titanium target is installed in the arc target of the coating machine, a φ75x650mm cylindrical titanium target is installed in the magnetron target 1, a φ75x650mm cylindrical tantalum or niobium target is installed in the magnetron target 2, and a φ75x650mm cylindrical zirconium-niobium target is installed in the magnetron target 3. The magnetron power supply uses a high-frequency pulse power supply. The cleaned and dried alloy base material is placed in the vacuum coating machine, and the initial temperature is 31°C. When the vacuum degree reaches 0.004pa, the coating is started. The process of the S1 electron beam enhanced plasma bombardment method is vacuum degree 1pa, cleaning time 90min, negative bias 200V, arc current 180A, and anode current 80A. The process of the S2 metal ion bombardment method is vacuum degree 0.1pa, bombardment time 300min, negative bias 400V, and magnetron sputtering current 30A. The process of the S3 metal deposition method is vacuum degree 0.5pa, negative bias 100V, magnetron sputtering current 80A, and time 8h. The coating end temperature is 75°C. The process of the S4 metal deposition method is vacuum degree 0.1pa, negative bias 200V, magnetron sputtering current 10A, and time 30h. The coating end temperature is 75°C. The temperature of the S5 heat treatment method is 550°C and the time is 8 hours.

[0047] The thickness of the tantalum or niobium layer is about 9 μm, the thickness of the zirconium-niobium alloy layer is about 22 μm, and the thickness of the zirconium-niobium (Zr-Nb-O) oxide layer is about 4 μm. After the coating is finished, the actual object can be seen to have a dense metal coating on the surface of the alloy base material. The surface hardness of the coating is 1000 HV. After 50 cycles of heating-cooling thermal shock from room temperature to 600°C, no microcracks are found on the surface of the coating.

[0048] Example 5:

[0049] The arc target in the coating machine is installed with a φ120x25mm circular arc titanium target, the magnetron target 1 is installed with a φ75x650mm cylindrical titanium target, the magnetron target 2 is installed with a φ75x650mm cylindrical tantalum or niobium target, the magnetron target 3 is installed with a φ75x650mm cylindrical zirconium niobium target, and the target magnetron power source adopts a high-frequency pulse power source. The cleaned and dried alloy base material is placed into the vacuum coating machine, and the initial temperature is 31℃. When the vacuum degree reaches 0.004pa, the coating begins. The vacuum degree in the process of the S1 electron beam enhanced plasma bombardment method is 1pa, the cleaning time is 90min, the negative bias is 200V, the arc current is 180A, and the anode current is 80A. The vacuum degree in the process of the S2 metal ion bombardment method is 0.1pa, the bombardment time is 300min, the negative bias is 400V, and the magnetron sputtering current is 30A. The vacuum degree in the process of the S3 metal deposition method is 0.5pa, the negative bias is 100V, the magnetron sputtering current is 80A, and the time is 8h. The coating end temperature is 75℃. The vacuum degree in the process of the S4 metal deposition method is 0.1pa, the negative bias is 260V, the magnetron sputtering current is 50A, and the time is 35h. The coating end temperature is 75℃. The temperature of the S5 heat treatment method is 550℃, and the time is 8 hours.

[0050] After testing, the thickness of the tantalum or niobium layer is about 8μm, the thickness of the zirconium niobium alloy layer is about 30μm, and the thickness of the zirconium niobium (Zr-Nb-O) oxide layer is about 4μm. After the coating is completed, it can be seen that the alloy base material surface has a dense metal coating, and the coating surface hardness reaches 900HV. After 50 times of cyclic heating-cooling thermal shock from room temperature to 600℃, no microcracks are observed on the coating surface.

[0051] Example 6:

[0052] The arc target in the coating machine is installed with a φ120x25mm circular arc titanium target, the magnetron target 1 is installed with a φ75x650mm cylindrical titanium target, the magnetron target 2 is installed with a φ75x650mm cylindrical tantalum or niobium target, the magnetron target 3 is installed with a φ75x650mm cylindrical zirconium niobium target, and the target magnetron power source adopts a high-frequency pulse power source. The cleaned and dried alloy base material is placed into the vacuum coating machine, and the initial temperature is 31℃. When the vacuum degree reaches 0.004pa, the coating begins. The vacuum degree in the process of the S1 electron beam enhanced plasma bombardment method is 1pa, the cleaning time is 90min, the negative bias is 200V, the arc current is 180A, and the anode current is 80A. The vacuum degree in the process of the S2 metal ion bombardment method is 0.1pa, the bombardment time is 300min, the negative bias is 400V, and the magnetron sputtering current is 30A. The vacuum degree in the process of the S3 metal deposition method is 0.5pa, the negative bias is 100V, the magnetron sputtering current is 80A, and the time is 8h. The coating end temperature is 75℃. The vacuum degree in the process of the S4 metal deposition method is 0.1pa, the negative bias is 320V, the magnetron sputtering current is 90A, and the time is 40h. The coating end temperature is 75℃. The temperature of the S5 heat treatment method is 550℃, and the time is 8 hours.

[0053] The thickness of the tantalum or niobium layer is about 8 μm, the thickness of the zirconium-niobium alloy layer is about 34 μm, and the thickness of the zirconium-niobium (Zr-Nb-O) oxide layer is about 4 μm. After the coating is finished, the actual product can be seen to have a dense metal coating on the surface of the alloy base material. The surface hardness of the coating is 1000 HV. After 50 cycles of heating-cooling thermal shock from room temperature to 600°C, no microcracks are observed on the surface of the coating.

[0054] Example 7

[0055] A φ120×25 mm circular arc titanium target is installed in the arc target of the coating machine, a φ75×650 mm cylindrical titanium target is installed in the magnetron target 1, a φ75×650 mm cylindrical tantalum or niobium target is installed in the magnetron target 2, and a φ75×650 mm cylindrical zirconium-niobium target is installed in the magnetron target 3. The magnetron power supply uses a high-frequency pulse power supply. The cleaned and dried alloy base material is placed in the vacuum coating machine, and the initial temperature is 31°C. When the vacuum degree reaches 0.004 Pa, the coating is started. The process of the S1 electron beam enhanced plasma bombardment method is vacuum degree 1 Pa, cleaning time 90 min, negative bias 200 V, arc current 180 A, and anode current 80 A. The process of the S2 metal ion bombardment method is vacuum degree 0.1 Pa, bombardment time 300 min, negative bias 400 V, and magnetron sputtering current 30 A. The process of the S3 metal deposition method is vacuum degree 0.5 Pa, negative bias 100 V, magnetron sputtering current 80 A, and time 8 h. The coating end temperature is 75°C. The process of the S4 metal deposition method is vacuum degree 0.1 Pa, negative bias 260 V, magnetron sputtering current 50 A, and time 35 h. The coating end temperature is 75°C. The temperature of the S5 heat treatment method is 500°C, and the time is 6 hours.

[0056] The thickness of the tantalum or niobium layer is about 8 μm, the thickness of the zirconium-niobium alloy layer is about 34 μm, and the thickness of the zirconium-niobium (Zr-Nb-O) oxide layer is about 4 μm. After the coating is finished, the actual product can be seen to have a dense metal coating on the surface of the alloy base material. The surface hardness of the coating is 1000 HV. After 50 cycles of heating-cooling thermal shock from room temperature to 600°C, no microcracks are observed on the surface of the coating.

[0057] Example 8

[0058] The arc target in the coating machine is installed with a φ120x25mm circular arc titanium target, the magnetron target 1 is installed with a φ75x650mm cylindrical titanium target, the magnetron target 2 is installed with a φ75x650mm cylindrical tantalum or niobium target, the magnetron target 3 is installed with a φ75x650mm cylindrical zirconium niobium target, and the target magnetron power source adopts a high-frequency pulse power source. The cleaned and dried alloy base material is placed into the vacuum coating machine, and the initial temperature is 31℃. When the vacuum degree reaches 0.004pa, the coating begins. The vacuum degree in the process of the S1 electron beam enhanced plasma bombardment method is 1pa, the cleaning time is 90min, the negative bias is 200V, the arc current is 180A, and the anode current is 80A. The vacuum degree in the process of the S2 metal ion bombardment method is 0.1pa, the bombardment time is 300min, the negative bias is 400V, and the magnetron sputtering current is 30A. The vacuum degree in the process of the S3 metal deposition method is 0.5pa, the negative bias is 100V, the magnetron sputtering current is 80A, and the time is 8h. The coating end temperature is 75℃. The vacuum degree in the process of the S4 metal deposition method is 0.1pa, the negative bias is 260V, the magnetron sputtering current is 50A, and the time is 35h. The coating end temperature is 75℃. The temperature of the S5 heat treatment method is 550℃, and the time is 8h.

[0059] After testing, the thickness of the tantalum or niobium layer is about 8μm, the thickness of the zirconium niobium alloy layer is about 30μm, and the thickness of the zirconium niobium (Zr-Nb-O) oxide layer is about 6μm. After the coating is completed, it can be seen that the alloy base material surface has a dense metal coating, and the coating surface hardness reaches 1002HV. After 50 times of cyclic heating-cooling thermal shock from room temperature to 600℃, no microcracks are observed on the coating surface.

[0060] Example 9:

[0061] The arc target in the coating machine is installed with a φ120x25mm circular arc titanium target, the magnetron target 1 is installed with a φ75x650mm cylindrical titanium target, the magnetron target 2 is installed with a φ75x650mm cylindrical tantalum or niobium target, the magnetron target 3 is installed with a φ75x650mm cylindrical zirconium niobium target, and the target magnetron power source adopts a high-frequency pulse power source. The cleaned and dried alloy base material is placed into the vacuum coating machine, and the initial temperature is 31℃. When the vacuum degree reaches 0.004pa, the coating begins. The vacuum degree in the process of the S1 electron beam enhanced plasma bombardment method is 1pa, the cleaning time is 90min, the negative bias is 200V, the arc current is 180A, and the anode current is 80A. The vacuum degree in the process of the S2 metal ion bombardment method is 0.1pa, the bombardment time is 300min, the negative bias is 400V, and the magnetron sputtering current is 30A. The vacuum degree in the process of the S3 metal deposition method is 0.5pa, the negative bias is 100V, the magnetron sputtering current is 80A, and the time is 8h. The coating end temperature is 75℃. The vacuum degree in the process of the S4 metal deposition method is 0.1pa, the negative bias is 260V, the magnetron sputtering current is 50A, and the time is 35h. The coating end temperature is 75℃. The temperature of the S5 heat treatment method is 600℃, and the time is 9h.

[0062] The tested tantalum or niobium layer has a thickness of about 8 μm, the zirconium niobium alloy layer has a thickness of about 30 μm, and the zirconium niobium (Zr-Nb-O) oxide layer has a thickness of about 9 μm. The actual product after the coating process can be seen to have a dense metal coating on the surface of the alloy substrate material. The surface hardness of the coating is 920 HV. After 50 cycles of heating-cooling thermal shock from room temperature to 600 °C, no microcracks are observed on the surface of the coating.

[0063] The data comparison of the coating process is as follows:

[0064] Comparative Example 1:

[0065] A φ120×25 mm circular arc titanium target is installed in the arc target of the coating machine, a φ75×650 mm cylindrical titanium target is installed in the magnetron target 1, a φ75×650 mm cylindrical tantalum or niobium target is installed in the magnetron target 2, and a φ75×650 mm cylindrical zirconium niobium target is installed in the magnetron target 3. The target magnetron power supply uses a high-frequency pulse power supply. The cleaned and dried alloy substrate material is placed in the vacuum coating machine, and the initial temperature is 31 °C. When the vacuum degree reaches 0.004 Pa, the coating process begins. The S1 electron beam enhanced plasma bombardment process has a vacuum degree of 1 Pa, a cleaning time of 90 min, a negative bias of 200 V, an arc current of 180 A, and an anode current of 80 A. The S2 metal ion bombardment process has a vacuum degree of 0.1 Pa, a bombardment time of 300 min, a negative bias of 400 V, and a magnetron sputtering current of 30 A. The S3 metal deposition process has a vacuum degree of 0.5 Pa, a negative bias of 100 V, a magnetron sputtering current of 80 A, and a time of 1 h. The coating end temperature is 75 °C. The S4 metal deposition process has a vacuum degree of 0.1 Pa, a negative bias of 260 V, a magnetron sputtering current of 50 A, and a time of 35 h. The coating end temperature is 75 °C. The S5 heat treatment process has a temperature of 600 °C and a time of 9 hours.

[0066] The tested tantalum or niobium layer has a thickness of about 1 μm, the zirconium niobium alloy layer has a thickness of about 31 μm, and the zirconium niobium (Zr-Nb-O) oxide layer has a thickness of about 9 μm. The surface hardness of the coating is 870 HV. The thickness of the pure tantalum layer in the composite coating is less than 5 μm. After 18 cycles of heating-cooling thermal shock from room temperature to 600 °C, microcracks appear on the surface of the coating.

[0067] Comparative Example 2:

[0068] The arc target in the coating machine is installed with a φ120x25mm round arc titanium target, the magnetron target 1 is installed with a φ75x650mm cylindrical titanium target, the magnetron target 2 is installed with a φ75x650mm cylindrical tantalum or niobium target, the magnetron target 3 is installed with a φ75x650mm cylindrical zirconium niobium target, and the target magnetron power supply adopts a high-frequency pulse power supply. The cleaned and dried alloy substrate material is placed in the vacuum coating machine, and the initial temperature is 31℃. When the vacuum degree reaches 0.004pa, the coating is started. The vacuum degree of the S1 electron beam enhanced plasma bombardment method process is 1pa, the cleaning time is 90min, the negative bias is 200V, the arc current is 180A, and the anode current is 80A. The vacuum degree of the S2 metal ion bombardment method process is 0.1pa, the bombardment time is 300min, the negative bias is 400V, and the magnetron sputtering current is 30A. The vacuum degree of the S3 metal deposition method process is 0.5pa, the negative bias is 100V, the magnetron sputtering current is 80A, and the time is 8h. The coating end temperature is 75℃. The vacuum degree of the S4 metal deposition method process is 0.1pa, the negative bias is 260V, the magnetron sputtering current is 50A, and the time is 12h. The coating end temperature is 75℃. The temperature of the S5 heat treatment method is 600℃, and the time is 9h.

[0069] After testing, the thickness of the tantalum or niobium layer is about 8μm, the thickness of the zirconium niobium alloy layer is about 12μm, the thickness of the zirconium niobium (Zr-Nb-O) oxide layer is about 8μm, and the surface hardness of the coating reaches 900HV. The thickness of the pure tantalum or niobium layer in the composite coating is not less than 5μm, but the thickness of the zirconium niobium alloy layer is not more than 3 times the thickness of the tantalum or niobium layer. After 28 cycles of room temperature to 600℃ cyclic heating-cooling thermal shock, microcracks are found on the surface of the coating.

[0070] Table 1 shows the comparison method and test results of each embodiment.

[0071]

[0072]

[0073] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above-described embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, and these simple modifications all belong to the protection scope of the present application.

[0074] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present application.

[0075] Furthermore, the various embodiments of the present application can be combined with each other, as long as it does not violate the spirit of the present application, and it should be considered as disclosed in the present application.

Claims

1. A vacuum plating method of a multilayer composite metal coating on a surface of an alloy substrate, characterized by, The method comprises the following steps: S1: polishing the alloy substrate, and cleaning the alloy substrate surface by argon ion electron beam enhanced plasma bombardment; S2: forming a transition layer by bombarding the alloy substrate surface with metal electron beam enhanced plasma generated by arc discharge; S3: performing first deposition by physical vapor deposition (PVD) method, and taking tantalum or niobium as target material for the metal film layer; S4: A second zirconium-niobium alloy layer is deposited in the same way, the metal film layer being denoted Zr 97.5 Nb 2.5 (wt%) zirconium-niobium alloy as target material; forming a multilayer composite coating through two times of metal deposition; S5: performing heat treatment on the coating to form a zirconium-niobium oxide layer to enhance the bonding force and compactness.

2. The method of claim 1, wherein, The alloy substrate is a titanium alloy substrate or a cobalt-chromium-molybdenum alloy substrate.

3. The method of claim 1, wherein, The parameters of the electron beam enhanced plasma cleaning are as follows: vacuum degree 1 Pa, negative bias voltage 150-250 V, arc current 150-200 A, and time 60-120 min.

4. The method of claim 1, wherein, The parameters of the metal ion bombardment are as follows: vacuum degree 0.1 Pa, negative bias voltage 300-500 V, magnetron sputtering current 20-40 A, and time 200-400 min.

5. The method of claim 1, wherein, The parameters of the first metal deposition are as follows: vacuum degree 0.5 Pa, negative bias voltage 40-200 V, magnetron sputtering current 10-100 A, and time 5-10 h; the parameters of the second metal deposition are as follows: vacuum degree 0.1 Pa, negative bias voltage 200-350 V, magnetron sputtering current 10-100 A, and time 30-40 h.

6. The method of claim 1, wherein, The heat treatment temperature is 500-620 ℃, and the time is 6-10 h.

7. The method of claim 1, wherein, The coating machine comprises an arc target and a plurality of magnetron targets, and the target materials include titanium, tantalum or niobium, and zirconium-niobium alloy.

8. The method of claim 1, wherein, The thickness of the pure tantalum or pure niobium layer is not less than 5 μm; the zirconium-niobium alloy component is Zr 97.5 Nb 2.5 (wt%) having a thickness greater than 3 times the thickness of the tantalum or niobium layer.

9. The method of claim 1, wherein, The final multilayer composite metal coating on the surface of the alloy substrate comprises a tantalum or niobium layer with a thickness of 5-10 μm, a zirconium-niobium alloy layer with a thickness of 20-35 μm, and a zirconium-niobium oxide layer with a thickness of 3-10 μm.

10. A medical alloy substrate implant, characterized in that, The surface of the alloy substrate is provided with a multilayer composite metal coating prepared by the method of any one of claims 1-7.

11. The implant of claim 10, wherein, The coating surface hardness is ≥655 HV, and the coating can withstand 50 times of thermal shock cycles below 600 ℃ without cracking.

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