A titanium-containing PVD oxide composite coating, its preparation method and application

Abstract

This invention discloses a titanium-containing PVD oxide composite coating, its preparation method, and its application. The preparation method includes the following steps: S1. Preparing a titanium-containing PVD coating on a substrate mold steel; S2. Under normal pressure, introducing an inert gas and heating to a temperature of 300–550°C, then introducing oxygen and an inert gas while controlling the oxygen / inert gas flow ratio to 0.3–1.0 to perform oxygen permeation oxidation on the titanium-containing PVD coating, thereby preparing the titanium-containing PVD oxide composite coating. The preparation method of the titanium-containing PVD oxide composite coating of this invention improves the density of the oxide film on the surface of the oxidized titanium-containing PVD coating by controlling the temperature and oxygen / inert gas flow ratio under normal pressure, thus improving the adhesion of the titanium-containing PVD oxide composite coating to the substrate mold steel, and also enhancing the wear resistance and anti-adhesion properties of the titanium-containing PVD oxide composite coating.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a titanium-containing PVD oxidation composite coating, its preparation method, and its application. Background Technology

[0002] PVD coatings, prepared using physical vapor deposition (PVD) technology, are widely used for surface protection of products such as molds and cutting tools due to their high hardness, wear resistance, and chemical stability. However, under certain service conditions, the high affinity between PVD coatings and the contact materials can easily lead to adhesion, reducing production efficiency and compromising product quality. For example, in aluminum alloy die casting, the PVD coating on the mold surface easily adheres to the molten aluminum, causing surface scratches on the aluminum alloy product or shortening the mold's service life. Similarly, during tool cutting, the cutting edge easily adheres to metal materials, forming a cutting edge, which reduces the surface quality of the machined product and also shortens the tool's life.

[0003] In recent years, researchers have discovered that coating the surface of a PVD coating with an oxide layer can effectively solve the above problems. Chinese patent CN110512173A discloses a method for simultaneous surface oxidation treatment of titanium-free PVD coatings for die-casting molds, successfully obtaining a dense oxide film on titanium-free PVD coatings through surface oxidation. However, this method is only applicable to titanium-free PVD coatings. It also points out that the Ti2O3 oxide obtained from the oxidation of titanium in titanium-containing PVD coatings has a loose and brittle structure and is easily broken under relatively small external loads, resulting in poor density of the oxide film on the surface of the titanium-containing PVD coating, thus limiting the application of titanium-containing PVD coatings.

[0004] Therefore, developing a method for preparing titanium-containing PVD oxide composite coatings that can improve the density of the oxide film on the surface of titanium-containing PVD coatings has significant economic value. Summary of the Invention

[0005] The primary objective of this invention is to address the problem of poor density of the oxide film on the surface of titanium-containing PVD coatings, and to provide a method for preparing a titanium-containing PVD oxide composite coating. The titanium-containing PVD oxide composite coating obtained by this method not only has a titanium oxide layer with high density, improving the density of the oxide film on the surface of the titanium-containing PVD coating, but also has high adhesion to the substrate mold steel, and at the same time has good wear resistance and anti-adhesion properties.

[0006] Another object of the present invention is to provide a titanium-containing PVD oxidation composite coating.

[0007] Another object of the present invention is to provide an application of a titanium-containing PVD oxide composite coating in the preparation of die-casting molds.

[0008] To achieve the above objectives, the present invention employs the following technical solutions:

[0009] A method for preparing a titanium-containing PVD oxidation composite coating includes the following steps:

[0010] S1. Prepare a titanium-containing PVD coating on a substrate mold steel;

[0011] S2. Under normal pressure, an inert gas is introduced and heated to a temperature of 300-550℃. Then, oxygen and inert gas are introduced and the oxygen / inert gas flow ratio is controlled to be 0.3-1.0 to perform oxygen permeation oxidation on the titanium-containing PVD coating to prepare a titanium-containing PVD oxidation composite coating.

[0012] This invention improves the density of the oxide film on the surface of the titanium-containing PVD coating after oxidation by controlling the temperature and the oxygen / inert gas flow ratio under normal pressure conditions. It also improves the adhesion of the titanium-containing PVD oxide composite coating to the substrate mold steel and enhances the wear resistance and anti-adhesion properties of the titanium-containing PVD oxide composite coating.

[0013] Specifically, this invention, under normal pressure conditions, performs oxygen permeation oxidation on a titanium-containing PVD coating by controlling the temperature and the oxygen / inert gas flow ratio. This not only yields various titanium oxides (TiO, TiO2, Ti2O3, Ti3O5, etc.) including Ti2O3, but also regulates the content of different titanium oxides and their alternating arrangement, enhancing the orderliness of the titanium oxide arrangement, reducing the gaps between titanium oxides, and allowing different types and contents of titanium oxides to be tightly and orderly superimposed, thereby forming a dense oxide layer. This improves the density of the oxide film on the surface of the titanium-containing PVD coating, as well as the adhesion of the titanium-containing PVD oxide composite coating to the substrate mold steel, and also enhances the wear resistance and anti-adhesion properties of the titanium-containing PVD oxide composite coating.

[0014] Furthermore, the reason why this invention chooses atmospheric pressure conditions instead of vacuum conditions is that, through numerous experiments, it was found that in the system of this invention, the oxidation rate of the titanium-containing PVD coating by oxygen under vacuum conditions is too fast and difficult to control, and it rapidly increases the thickness of the oxide layer, making the oxide layer loose and brittle, reducing the density of the titanium oxide structure, and also reducing the density of the oxide film on the surface of the titanium-containing PVD coating. Under atmospheric pressure conditions, this invention can effectively control the oxidation rate of the titanium-containing PVD coating, promote the close and orderly stacking of titanium oxides, thereby forming a dense oxide layer and improving the density of the oxide film on the surface of the titanium-containing PVD coating.

[0015] Furthermore, in this invention, the entire process of step S2 is maintained under normal pressure conditions.

[0016] Preferably, the oxygen / inert gas flow ratio in step S2 is 0.4 to 1.

[0017] More preferably, the oxygen / inert gas flow ratio in step S2 is 0.5 to 1.

[0018] In this invention, when the oxygen / inert gas flow ratio is too high (>1), the density of the oxide film on the surface of the titanium-containing PVD coating will be reduced; while when the oxygen / inert gas flow ratio is too low (<0.5), although a dense oxide film can be formed on the surface of the titanium-containing PVD coating, the thickness of the oxide film is too thin, the wear resistance is poor, and the wear is too fast in the actual process.

[0019] Preferably, the oxygen flow rate in step S2 is 200–1000 sccm.

[0020] Preferably, the flow rate of the inert gas in step S2 is 200–3400 sccm.

[0021] More preferably, the flow rate of the inert gas in step S2 is 200-2500 sccm.

[0022] During the experiment, the inventors discovered that, under the same oxygen / inert gas flow rate ratio, neither the amount of oxygen flow nor the amount of inert gas flow would affect the density of the oxide film on the surface of the titanium-containing PVD coating after oxidation, the adhesion of the titanium-containing PVD oxide composite coating to the substrate mold steel, or the wear resistance and anti-adhesion properties of the titanium-containing PVD oxide composite coating.

[0023] Preferably, the temperature in step S2 is 500–540°C.

[0024] Preferably, the base mold steel in step S1 is one or more of 8407 mold steel, H13 mold steel, or 8418 mold steel.

[0025] Preferably, the base mold steel described in step S1 is polished, cleaned, and dried before use.

[0026] More preferably, the polishing is to polish the base mold steel to a roughness of ≤0.1μm.

[0027] Preferably, the titanium-containing PVD coating in step S1 is one or both of nitrogen-doped titanium-containing PVD coating and non-nitrogen-doped titanium-containing PVD coating.

[0028] More preferably, the nitrogen-doped titanium-containing PVD coating is one or more of TiN coating, TiAlN coating, TiSiN coating or TiCrN coating.

[0029] More preferably, the nitrogen-free titanium-containing PVD coating is one or both of a Ti coating or a TiSi coating.

[0030] Preferably, the thickness of the titanium-containing PVD coating in step S1 is 0.2–10 μm.

[0031] Preferably, the specific operation of step S1 is as follows: placing the substrate mold steel into the substrate holder of the PVD furnace, opening the titanium-containing target, introducing nitrogen gas, adjusting the PVD deposition parameters, and preparing a titanium-containing PVD coating.

[0032] More preferably, the titanium-containing target material is one or more of titanium (Ti) target, titanium-aluminum (TiAl) alloy, titanium-silicon (TiSi) alloy or titanium-chromium (TiCr) alloy.

[0033] More preferably, the PVD deposition parameters are as follows: PVD furnace pressure 0.8–6.0 Pa, titanium-containing target current 60–200 A, substrate bias voltage -40–-200 V, nitrogen flow rate 200–1000 sccm, deposition temperature 300–600 °C, and deposition time 1–10 h.

[0034] Preferably, the thickness of the oxide layer of the titanium-containing PVD oxide composite coating in step S2 is 40–260 nm.

[0035] Preferably, the specific operation of step S2 is as follows: under normal pressure, the titanium-containing PVD coating is fed into an atmosphere protection furnace, an inert gas is introduced, and the temperature is heated to 300-550°C. Then, oxygen and inert gas are introduced and the oxygen / inert gas flow ratio is controlled to be 0.3-1.0 to perform oxygen permeation oxidation on the titanium-containing PVD coating to prepare a titanium-containing PVD oxidation composite coating.

[0036] More preferably, the inert gas is one or both of argon and nitrogen.

[0037] A titanium-containing PVD oxidation composite coating is prepared by the above-described preparation method.

[0038] The application of the above-mentioned titanium-containing PVD oxide composite coating in the preparation of die-casting molds should also be within the scope of protection of this invention.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] The preparation method of the titanium-containing PVD oxide composite coating of the present invention, based on atmospheric pressure conditions, involves oxygen permeation oxidation of the titanium-containing PVD coating by controlling the temperature and oxygen / inert gas flow ratio. This not only yields various titanium oxides (TiO, TiO2, Ti2O3, Ti3O5, etc.) including Ti2O3, but also regulates the content of different titanium oxides and their alternating arrangement, enhancing the orderliness of the titanium oxide arrangement, reducing the gaps between titanium oxides, and allowing different types and contents of titanium oxides to be tightly and orderly superimposed, thereby forming a dense oxide layer. This improves the density of the oxide film on the surface of the titanium-containing PVD coating, the adhesion of the titanium-containing PVD oxide composite coating to the substrate mold steel, and also enhances the wear resistance and anti-adhesion properties of the titanium-containing PVD oxide composite coating. Attached Figure Description

[0041] Figure 1 These are SEM images of the cross-sections of the surface oxide films of the titanium-containing PVD oxide composite coatings in Example 5 and Comparative Example 4. Figure 1 A is a SEM image of the cross-section of the surface oxide film of the titanium-containing PVD oxide composite coating in Comparative Example 4. Figure 1 B is a SEM image of the cross-section of the surface oxide film of the titanium-containing PVD oxide composite coating in Example 5. Detailed Implementation

[0042] The present invention is further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from the conventional market. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention are within the scope of protection claimed by the present invention.

[0043] Example 1

[0044] This embodiment provides a method for preparing a titanium-containing PVD oxidation composite coating, including the following steps:

[0045] S1. Polish 8407 mold steel to a roughness ≤0.1μm, then ultrasonically clean it with acetone and anhydrous ethanol for 30min in sequence, and dry it with an air gun. Place it on the substrate holder of the PVD furnace, open the titanium (Ti) target containing titanium, introduce nitrogen gas, and adjust the PVD deposition parameters as follows: PVD furnace pressure 2.0Pa, titanium target current 160A, substrate bias voltage -80V, nitrogen flow rate 500sccm, deposition temperature 420℃ and deposition time 1h to prepare titanium-containing PVD coating TiN;

[0046] S2. Under normal pressure, the titanium-containing PVD-coated TiN is fed into an atmosphere-protected furnace, inert gas nitrogen is introduced, and the temperature is heated to 520℃. Then oxygen and inert gas nitrogen are introduced and the oxygen / nitrogen flow ratio is controlled to be 0.8. The titanium-containing PVD-coated TiN is subjected to oxygen permeation oxidation for 2 hours to prepare a titanium-containing PVD-oxidized composite coating.

[0047] In step S1, the thickness of the titanium-containing PVD coating TiN is 1.0 μm, the oxygen flow rate in step S2 is 700 sccm, the nitrogen flow rate in step S2 is 875 sccm, and the entire process in step S2 is maintained under normal pressure.

[0048] A titanium-containing PVD oxidation composite coating is prepared by the above-described preparation method.

[0049] Examples 2-6 and Comparative Example 1

[0050] Examples 2-6 and Comparative Example 1 provide different methods for preparing titanium-containing PVD oxide composite coatings. The only differences from Example 1 are the oxygen / nitrogen flow rate ratio and the nitrogen flow rate in step S2. All other methods are the same as in Example 1, as shown in the table below:

[0051] Table 1 shows the oxygen / nitrogen flow rate ratio, oxygen flow rate, and nitrogen flow rate in step S2 of Examples 1-6 and Comparative Example 1.

[0052] Oxygen / nitrogen flow ratio Oxygen flow rate / sccm Nitrogen flow rate / sccm Example 1 0.8 700 875 Example 2 0.7 700 1000 Example 3 0.9 700 777 Example 4 0.5 700 1400 Example 5 1.0 700 700 Example 6 0.4 700 1750 Comparative Example 1 1.1 700 636

[0053] Examples 7-10 and Comparative Examples 2-3

[0054] Examples 7-10 and Comparative Examples 2-3 provide different methods for preparing titanium-containing PVD oxide composite coatings. The only difference from Example 1 is the temperature in step S2; all other methods are the same as in Example 1, as shown in the table below:

[0055] Table 2 Temperatures in step S2 of Examples 1, 7-10 and Comparative Examples 2-3

[0056]

[0057]

[0058] Example 11

[0059] This embodiment provides a method for preparing a titanium-containing PVD oxidation composite coating. The only difference from Example 1 is that the oxygen flow rate in step S2 is 1000 sccm and the nitrogen flow rate in step S2 is 1250 sccm. All other aspects are the same as in Example 1.

[0060] Example 12

[0061] This embodiment provides a method for preparing a titanium-containing PVD oxidation composite coating. The only difference from Embodiment 1 is that in step S1, a titanium-containing target material, titanium-aluminum (TiAl) alloy, is used instead of a titanium (Ti) target. All other aspects are the same as in Embodiment 1.

[0062] In step S1, the thickness of the titanium-containing PVD coating TiAlN is 1.0 μm.

[0063] Example 13

[0064] This embodiment provides a method for preparing a titanium-containing PVD oxidation composite coating. The only difference from Embodiment 1 is that in step S1, a titanium-containing target material, titanium-silicon (TiSi) alloy, is used instead of a titanium (Ti) target. All other aspects are the same as in Embodiment 1.

[0065] In step S1, the thickness of the titanium-containing PVD coating TiSiN is 3.0 μm.

[0066] Comparative Example 4

[0067] This comparative example provides a method for preparing a titanium-containing PVD oxide composite coating. The only difference from Example 1 is that air is used instead of oxygen and inert nitrogen in step S2, as detailed below:

[0068] S1. Consistent with Example 1;

[0069] S2. Under normal pressure, the titanium-containing PVD-coated TiN is fed into an atmosphere-protected furnace, inert gas nitrogen is introduced, and the temperature is heated to 520℃. Then the atmosphere-protected furnace is opened to allow air to be introduced, and the titanium-containing PVD-coated TiN is subjected to oxygen permeation oxidation for 2 hours to prepare a titanium-containing PVD-oxidized composite coating.

[0070] In step S1, the thickness of the titanium-containing PVD coating TiN is 1.0 μm, and the entire process of step S2 is maintained under normal pressure conditions.

[0071] Comparative Example 5

[0072] This comparative example provides a method for preparing a titanium-containing PVD oxidation composite coating. The only difference from Example 1 is that oxygen is used instead of oxygen and inert gas nitrogen in step S2, and the oxygen flow rate is 700 sccm. All other aspects are the same as in Example 1.

[0073] Comparative Example 6

[0074] This comparative example provides a method for preparing a titanium-containing PVD oxidation composite coating, referring to Example 1 of Chinese Patent CN110512173A, but replacing the Cr target and AlCrSi target in Example 1 of Chinese Patent CN110512173A with titanium (Ti) target and titanium silicon (TiSi) alloy target.

[0075] Sample characterization

[0076] Figure 1 These are SEM images of the cross-sections of the surface oxide films of the titanium-containing PVD oxide composite coatings in Example 5 and Comparative Example 4. Figure 1 A is a SEM image of the cross-section of the surface oxide film of the titanium-containing PVD oxide composite coating in Comparative Example 4. Figure 1 B is a SEM image of the cross-section of the surface oxide film of the titanium-containing PVD oxide composite coating in Example 5. From... Figure 1 It can be seen that the surface oxide film obtained by oxygen permeation oxidation of the titanium-containing PVD coating in Comparative Example 4 has a loose structure and poor density; while the surface oxide film obtained by oxygen permeation oxidation of the titanium-containing PVD coating in Example 5, which controls the oxygen / nitrogen flow ratio to 1.0, has a dense structure and high density. This is because air contains not only oxygen and the inert gas nitrogen, but also other gases and impurities such as rare gases. These rare gases and other gases and impurities can lead to a loose surface oxide film structure of the titanium-containing PVD coating, reducing the density of the surface oxide film.

[0077] Performance testing

[0078] The surface oxide film density, adhesion, wear resistance, and anti-adhesion properties of the titanium-containing PVD oxide composite coatings in each embodiment and comparative example were tested.

[0079] (1) Test on the density of surface oxide film

[0080] Samples with titanium-containing PVD oxide composite coatings from each embodiment and comparative example were broken and then placed in an SEM. The microstructure of the surface oxide film cross-section was observed using backscattered electrons. Five different points were taken from each group of samples for testing. The thickness and density of the surface oxide film of the titanium-containing PVD oxide composite coatings from each embodiment and comparative example were measured and recorded.

[0081] (2) Bonding strength test of the base mold steel

[0082] Using a Rockwell hardness tester, the indentation was pressed into the surface of the titanium-containing PVD oxide composite coating in each embodiment or comparative example under a load of 150 kg. The coating peeling around the indentation was then observed using a metallographic microscope, and the adhesion strength was rated. The adhesion strength grade characterizes the bonding strength of the titanium-containing PVD oxide composite coating to the substrate mold steel. Adhesion strength grades are HF1, HF2, HF3, HF4, HF5, and HF6, where HF1 indicates the strongest adhesion and HF6 indicates the weakest adhesion. The specific reference is to the international standard ISO 26443:2008.

[0083] (3) Wear resistance test

[0084] The friction coefficients of the titanium-containing PVD oxide composite coatings in each embodiment and comparative example were tested using a room temperature friction and wear tester. The smaller the friction coefficient, the better the wear resistance of the titanium-containing PVD oxide composite coating.

[0085] (4) Anti-adhesion performance test

[0086] Each embodiment or comparative example of titanium-containing PVD anodized composite coating was placed in an air furnace. A 6mm diameter aluminum ball was placed on the surface of each titanium-containing PVD anodized composite coating. The furnace was then heated to 800°C until the aluminum ball was completely melted. A 3mm diameter stainless steel wire was then inserted into the melt and cooled and solidified together. Finally, a handheld force gauge was used to test the adhesion between the aluminum ball and the titanium-containing PVD anodized composite coating. The higher the adhesion, the worse the anti-adhesion performance of the titanium-containing PVD anodized composite coating.

[0087] The experimental test results are shown in Table 3.

[0088] Table 3 Performance test results of titanium-containing PVD oxide composite coatings in each embodiment and comparative example

[0089]

[0090]

[0091] In the table, " / " indicates that the surface oxide film of the titanium-containing PVD oxide composite coating is too thin to be measured by SEM.

[0092] As can be seen from Table 3:

[0093] (1) The surface oxide film of the titanium-containing PVD oxide composite coating in Examples 1 to 6 is dense, while the surface oxide film of the titanium-containing PVD oxide composite coating in Comparative Example 1 is loose. This indicates that when the oxygen / inert gas flow ratio is 0.3 to 1.0, it is beneficial to improve the density of the surface oxide film of the titanium-containing PVD coating. In addition, the bonding strength of Examples 1 to 5 to the substrate mold steel is greater than that of Comparative Example 1. The friction coefficient and the bonding strength between the aluminum ball and the titanium-containing PVD oxide composite coating in Examples 1 to 5 are both less than those in Comparative Example 1. This indicates that when the oxygen / inert gas flow ratio is 0.5 to 1, it is also possible to better improve the bonding strength of the titanium-containing PVD oxide composite coating to the substrate mold steel, as well as its wear resistance and anti-adhesion properties.

[0094] (2) The surface oxide film of the titanium-containing PVD oxide composite coatings in Examples 1, 7-10 has a higher density and a stronger adhesion to the substrate mold steel than that in Comparative Examples 2-3. Furthermore, the adhesion between the aluminum balls in Examples 1, 7-10 and the titanium-containing PVD oxide composite coating is lower than that in Comparative Examples 2-3. This indicates that when the temperature is 300-550℃, it is beneficial to improve the density of the surface oxide film of the titanium-containing PVD coating, the adhesion of the titanium-containing PVD oxide composite coating to the substrate mold steel, and its anti-adhesion performance. In addition, the coefficient of friction of Examples 1, 7-8 and 10 is lower than that of Comparative Examples 2-3, indicating that when the temperature is 500-550℃, the titanium-containing PVD oxide composite coating has better wear resistance.

[0095] (3) The surface oxide film thickness, surface oxide film density, bonding strength to the substrate mold steel, friction coefficient, and bonding strength between the aluminum ball and the titanium-containing PVD oxide composite coating in Example 11 are consistent with those in Example 1. This indicates that under the same oxygen / inert gas flow rate ratio, the magnitude of oxygen flow rate and nitrogen flow rate will not affect the density of the surface oxide film of the titanium-containing PVD coating after oxidation, the bonding strength of the titanium-containing PVD oxide composite coating to the substrate mold steel, and the wear resistance and anti-adhesion performance of the titanium-containing PVD oxide composite coating.

[0096] (4) In Example 1, which uses oxygen and inert gas, the density of the surface oxide film of the titanium-containing PVD oxide composite coating and the bonding strength to the substrate mold steel are stronger than those of Comparative Example 4, which uses air, and Comparative Example 5, which uses oxygen. Furthermore, the coefficient of friction and the bonding strength between the aluminum ball and the titanium-containing PVD oxide composite coating in Example 1 are both lower than those in Comparative Examples 4 and 5. This indicates that compared to air and pure oxygen conditions, using only oxygen and inert gas can not only improve the density of the surface oxide film of the titanium-containing PVD coating after oxidation and the bonding strength of the titanium-containing PVD oxide composite coating to the substrate mold steel, but also enhance the wear resistance and anti-adhesion properties of the titanium-containing PVD oxide composite coating.

[0097] (5) The surface oxide film of the titanium-containing PVD oxide composite coating in Example 1 has a higher density and a stronger adhesion to the substrate mold steel than that in Comparative Example 6. Furthermore, the friction coefficient and the adhesion between the aluminum ball and the titanium-containing PVD oxide composite coating in Example 1 are both lower than those in Comparative Example 6. This indicates that the preparation method of the titanium-containing PVD oxide composite coating of the present invention solves the problem of poor density of the surface oxide film of the titanium-containing PVD coating prepared by the method of Chinese Patent CN110512173A. At the same time, it also improves the adhesion of the titanium-containing PVD oxide composite coating to the substrate mold steel and enhances the wear resistance and anti-adhesion performance of the titanium-containing PVD oxide composite coating.

[0098] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a titanium-containing PVD oxide composite coating, characterized in that, Includes the following steps: S1. Prepare a titanium-containing PVD coating on a substrate mold steel; S2. Under normal pressure, an inert gas is introduced and heated to a temperature of 300~550℃. Then, oxygen and inert gas are introduced and the oxygen / inert gas flow ratio is controlled to be 0.5~1.0 to perform oxygen permeation oxidation on the titanium-containing PVD coating to prepare a titanium-containing PVD oxidation composite coating. The specific operation of step S1 is as follows: place the substrate mold steel into the substrate holder of the PVD furnace, open the titanium-containing target, introduce nitrogen gas, adjust the PVD deposition parameters, and prepare a titanium-containing PVD coating.

2. The preparation method according to claim 1, characterized in that, The temperature mentioned in step S2 is 500~540℃.

3. The preparation method according to claim 1, characterized in that, The titanium-containing target material is one or more of titanium target, titanium-aluminum alloy, titanium-silicon alloy or titanium-chromium alloy.

4. The preparation method according to claim 1, characterized in that, The titanium-containing PVD coating mentioned in step S1 is a nitrogen-doped titanium-containing PVD coating; the nitrogen-doped titanium-containing PVD coating is one or more of TiN coating, TiAlN coating, TiSiN coating or TiCrN coating.

5. The preparation method according to claim 1, characterized in that, In step S2, the thickness of the oxide layer of the titanium-containing PVD oxide composite coating is 40~260nm.

6. A titanium-containing PVD oxidation composite coating, characterized in that, It is prepared by any of the preparation methods described in claims 1 to 5.

7. The application of the titanium-containing PVD oxide composite coating as described in claim 6 in the preparation of die-casting molds.

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