1. A preparation method of a toughened CrTiNiSiN nano composite coating is characterized by comprising the following steps:

1) performing mirror polishing and ultrasonic cleaning on the substrate;

2) respectively installing a Ti target and a Cr target on a direct current target, installing a Si target and a CrNi target on a radio frequency target, clamping a base material on a sample table, closing a sealing cover, changing the vacuum degree of a deposition cavity, and bombarding the surface of the base material by using argon ions to clean and remove dirt;

3) depositing a transition Cr layer;

4) depositing a CrN coating;

5) and depositing a CrTiNiSiN coating.

2. The preparation method of the strengthening and toughening CrTiNiSiN nano composite coating according to claim 1, characterized in that: the method comprises the following steps of 1) performing mirror polishing and ultrasonic cleaning on a base material, specifically, performing mirror polishing on the base material on a metallographic polishing machine, firstly performing rough polishing by using w20 diamond powder and matching with rough polishing canvas, then performing fine polishing by using w2.5 diamond powder and matching with fine polishing flannelette, and performing ultrasonic cleaning in an alcohol solution for 20-30 minutes after the base material is cleaned by fine polishing.

3. The preparation method of the strengthening and toughening CrTiNiSiN nano composite coating according to claim 1, characterized in that: in the step 2), the vacuum degree of the deposition cavity is pumped to 2.5 multiplied by 10^-3～3.0×10^-3Pa, argon ion flow rate of 20sccm, substrate bias of-500V.

4. The preparation method of the strengthening and toughening CrTiNiSiN nano composite coating according to claim 1, characterized in that: in the step 2), the target purities of the Ti target and the Cr target are 99.9%, the target purities of the Si target and the CrNi target are 99.99%, and the CrNi target is an alloy target with 20% of Cr and 80% of Ni.

5. The preparation method of the strengthening and toughening CrTiNiSiN nano composite coating according to claim 1, characterized in that: and 3) depositing the transition Cr layer, specifically, maintaining the working gas pressure of the deposition cavity at 0.10-0.15 Pa, preparing at 180-250 ℃, rotating the substrate at a speed of 5 revolutions per minute, flowing Ar gas at 20sccm, biasing the substrate at-60V, and depositing the transition Cr layer for 10 minutes at a Cr target current of 4A.

6. The method for preparing the strengthening and toughening CrTiNiSiN nano composite coating according to claim 5, characterized in that: and 4) depositing the CrN coating, wherein the pressure of working gas in a deposition cavity is kept at 0.10-0.15 Pa, the preparation temperature is 180-250 ℃, the rotating speed of the substrate is 5 revolutions per minute, the flow rate of Ar is 20sccm, the bias voltage of the substrate is-60V, and the Cr target current is 4A, N₂The flow rate was 8sccm and deposition was for 30 minutes.

7. The method for preparing the strengthening and toughening CrTiNiSiN nano composite coating according to claim 6, characterized in that: and 5) depositing the CrTiNiSiN coating, wherein the pressure of working gas in a deposition cavity is kept at 0.10-0.15 Pa, the preparation temperature is 180-250 ℃, the rotating speed of a base material is 5 revolutions per minute, the flow of Ar gas is 20sccm, the bias voltage of the base material is-60V, the currents of Cr and Ti targets are 4A, the power of a Si target is 1000W, the power of a CrNi target is 400-1200W, and the CrTiNiSiN composite film is prepared, wherein the deposition time is 180 minutes.

8. The preparation method of the strengthening and toughening CrTiNiSiN nano composite coating according to claim 1, characterized in that: the base material is a hard alloy sample substrate.

9. The preparation method of the strengthening and toughening CrTiNiSiN nano composite coating according to claim 1, characterized in that: the thickness of the transition Cr layer is 100nm, the thickness of the CrN coating is 400nm, and the thickness of the CrTiNiSiN coating is 2.5 mu m.

Background

According to the Archard wear model V ═ K (PL)/H, the wear volume (V) of a material is inversely proportional to its hardness (H), and therefore the synthesis of ultrahard (H >40GPa) coatings is a goal that researchers always pursue. However, the toughness of the conventional homogeneous coating is greatly reduced while the hardness is improved, and an inverted relationship between the strength and the toughness occurs. I.e., the higher the hardness of the coating, the greater the brittleness, and the less tough it is, resulting in less resistance to crack propagation. The problem of poor toughness of the coating is gradually highlighted in the application, such as in the application of frictional wear, erosion protection and the like, when cracks are generated on the surface of the hard coating, the wear resistance of the hard coating depends on the toughness of the hard coating. The CrTiSiN coating has high hardness and can reach superhard hardness, but the high hardness of the CrTiSiN coating causes poor toughness, and when the CrTiSiN coating is used as a cutter coating or a key part protective coating, crack failure easily occurs under periodic impact load.

Common methods for toughening a coating include texture structure toughening, residual compressive stress toughening, structural design toughening, toughness phase toughening and the like, but each toughening method has certain defects. For toughness phase toughening, soft metal Ni is the most commonly used doping phase, and the main reason is that Ni has good oxidation resistance, and element Ni is difficult to combine with elements Ti, Cr, Zr and N to form a compound and exists in a transition metal nitride film in a free state, so that the good toughness characteristic of the transition metal nitride film is maintained; however, the introduction of the soft phase metal Ni leads to a great reduction in hardness and abrasion resistance with an increase in the content, and therefore, it is necessary to control the Ni content well.

For structural toughening, a multilayer structure is often formed by soft metals (Ni, Cu, etc.) and hard coatings, and the multilayer structure can effectively improve the toughness of the coatings. However, Ni and Cu cannot form a compound phase with the transition metal nitride, and thus, the quality and bonding force of the interlayer interface are poor, and delamination easily occurs to fail. In view of the limitation of a single toughening method, the synergistic effect of multiple toughening methods has become a trend of toughening development of hard coatings.

Disclosure of Invention

The invention aims to provide a preparation method of a toughened CrTiNiSiN nano composite coating, which realizes stable transition of interlayer phases and effectively improves the quality and the bonding force of an interlayer interface; the section forms a gradient with gradually increased hardness, and the integral load resistance of the composite coating is effectively improved; by optimizing the preparation process, the hardness value is effectively ensured on the premise of toughening.

In order to achieve the above object, according to one aspect of the present invention, the present invention provides the following technical solutions:

a preparation method of a toughened CrTiNiSiN nano composite coating comprises the following steps:

1) performing mirror polishing and ultrasonic cleaning on the substrate;

2) respectively installing a Ti target and a Cr target on a direct current target, installing a Si target and a CrNi target on a radio frequency target, clamping a base material on a sample table, closing a sealing cover, changing the vacuum degree of a deposition cavity, and bombarding the surface of the base material by using argon ions to clean and remove dirt;

3) depositing a transition Cr layer;

4) depositing a CrN coating;

5) and depositing a CrTiNiSiN coating.

The invention is further configured to: the method comprises the following steps of 1) performing mirror polishing and ultrasonic cleaning on a base material, specifically, performing mirror polishing on the base material on a metallographic polishing machine, firstly performing rough polishing by using w20 diamond powder and matching with rough polishing canvas, then performing fine polishing by using w2.5 diamond powder and matching with fine polishing flannelette, and performing ultrasonic cleaning in an alcohol solution for 20-30 minutes after the base material is cleaned by fine polishing.

The invention is further configured to: in the step 2), the vacuum degree of the deposition cavity is pumped to 2.5 multiplied by 10^-3～3.0×10^{- 3}Pa, argon ion flow rate of 20sccm, substrate bias of-500V.

The invention is further configured to: in the step 2), the target purities of the Ti target and the Cr target are 99.9%, the target purities of the Si target and the CrNi target are 99.99%, and the CrNi target is an alloy target with 20% of Cr and 80% of Ni.

The invention is further configured to: and 3) depositing the transition Cr layer, specifically, maintaining the working gas pressure of the deposition cavity at 0.10-0.15 Pa, preparing at 180-250 ℃, rotating the substrate at a speed of 5 revolutions per minute, flowing Ar gas at 20sccm, biasing the substrate at-60V, and depositing the transition Cr layer for 10 minutes at a Cr target current of 4A.

The invention is further configured to: and 4) depositing the CrN coating, wherein the pressure of working gas in a deposition cavity is kept at 0.10-0.15 Pa, the preparation temperature is 180-250 ℃, and the rotating speed of the base material is 5 min/minIn turn, Ar gas flow 20sccm, substrate bias-60V, Cr target current 4A, N₂The flow rate was 8sccm and deposition was for 30 minutes.

The invention is further configured to: and 5) depositing the CrTiNiSiN coating, wherein the pressure of working gas in a deposition cavity is kept at 0.10-0.15 Pa, the preparation temperature is 180-250 ℃, the rotating speed of a base material is 5 revolutions per minute, the flow of Ar gas is 20sccm, the bias voltage of the base material is-60V, the currents of Cr and Ti targets are 4A, the power of a Si target is 1000W, the power of a CrNi target is 400-1200W, and the CrTiNiSiN composite film is prepared, wherein the deposition time is 180 minutes.

The invention is further configured to: the base material is a hard alloy sample substrate.

The invention is further configured to: the thickness of the transition Cr layer is 100nm, the thickness of the CrN coating is 400nm, and the thickness of the CrTiNiSiN coating is 2.5 mu m.

Compared with the prior art, the invention has the advantages that: the coating adopts a Cr-CrN-CrTiNiSiN multilayer structure, and CrN is present at the interlayer interfaces_xThe stable transition of the interlayer phase is realized, and the interlayer interface quality and the bonding force are effectively improved; the gradient with gradually increased hardness is formed on the section of the Cr/CrN/CrTiNiSiN composite coating, so that the integral load resistance of the composite coating can be effectively improved; by optimizing the preparation process, the doping amount of the soft-phase metal Ni and the content of other element components in the coating are controlled to generate (Cr, Ti) N crystal phase embedded in the a-Si₃N₄In the amorphous matrix, amorphous phase Ni exists between (Cr, Ti) N crystal grains in the form of solid solution, and the solid solution strengthening effect and the nano composite structure nc- (Cr, Ti) N/a-Si₃N₄The hardness value is effectively ensured on the premise of toughening.

Drawings

FIG. 1 is a scanning electron microscope image of the cross-sectional morphology of the Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 1;

FIG. 2 is a nanoindentation morphology of the Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 1;

FIG. 3 is a scanning electron microscope image of the cross-sectional morphology of the Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 2;

FIG. 4 is a nanoindentation morphology of the Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 2;

FIG. 5 is a scanning electron microscope image of the cross-sectional morphology of the Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 3;

FIG. 6 is a nanoindentation morphology of the Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 3;

FIG. 7 is a schematic view of a Cr/CrN/CrTiNiSiN multilayer nanocomposite coating;

Detailed Description

The invention is further described with reference to the accompanying drawings.

FIG. 7 is a schematic diagram of the prepared Cr/CrN/CrTiNiSiN multilayer nanocomposite coating.

Example 1:

the invention provides a preparation method of a toughened CrTiNiSiN nano composite coating, which comprises the following steps:

1) performing mirror polishing and ultrasonic cleaning on the substrate;

carrying out mirror polishing and ultrasonic cleaning on a hard alloy sample substrate, carrying out mirror polishing on the hard alloy sample substrate on a metallographic polishing machine, firstly carrying out rough polishing by using w20 diamond powder and matching with rough polishing canvas, then carrying out fine polishing by using w2.5 diamond powder and matching with fine polishing flannelette, and carrying out ultrasonic cleaning for 20 minutes in an alcohol solution after the substrate is cleaned by fine polishing.

2) Respectively installing a Ti target and a Cr target with the target purity of 99.9% on a direct current target, installing a Si target and a CrNi target with the target purity of 99.99% on a radio frequency target, clamping a base material on a sample table, closing a sealing cover, changing the vacuum degree of a deposition cavity, and bombarding the surface of the base material by using argon ions to clean and remove dirt, wherein the CrNi target is an alloy target with the Cr content of 20% and the Ni content of 80%; wherein the vacuum degree of the deposition chamber is pumped to 2.5 multiplied by 10^-3Pa, argon ion flow rate of 20sccm, substrate bias of-500V.

3) Depositing a transition Cr layer;

the pressure of working gas in the deposition cavity is kept at 0.10Pa, a heating source is not started in the film deposition process, the preparation temperature is 180 ℃, the rotating speed of the substrate is 5 revolutions per minute, the flow rate of Ar is 20sccm, the bias voltage of the substrate is-60V, the current of a Cr target is 4A, and a transitional Cr layer is deposited for 10 minutes.

4) Depositing a CrN coating;

the pressure of working gas in the deposition chamber is kept at 0.10Pa, no heating source is started in the film deposition process, the preparation temperature is 180 ℃, the rotating speed of the substrate is 5 r/min, the flow of Ar is 20sccm, the bias voltage of the substrate is-60V, and the Cr target current is 4A, N₂The flow rate was 8sccm and deposition was for 30 minutes.

5) Depositing a CrTiNiSiN coating;

the working gas pressure of the deposition cavity is kept at 0.10Pa, a heating source is not started in the film deposition process, the preparation temperature is 180 ℃, the rotating speed of the base material is 5 revolutions per minute, the flow of Ar is 20sccm, the bias voltage of the base material is-60V, the target currents of Cr and Ti are both 4A, the power of Si target is 1000W, and the power of CrNi target is 400W, and the CrTiNiSiN composite film is prepared, wherein the deposition time is 180 minutes.

The sectional morphology scanning electron microscope image of the Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 1 is shown in FIG. 1.

The Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 1 had a Cr content of 63.1 at.%, a Ti content of 9.1 at.%, a Ni content of 0.9 at.%, a Si content of 0.7 at.%, and an N content of 26.2 at.%; the nano-hardness of the Cr/CrN/CrTiNiSiN multilayer nano-composite coating is 48.5GPa, and the elastic modulus is 512.5 GPa; after the coating is pressed into the coating with the depth of 1 mu m by using a nano indentation large load, no radioactive crack is found at the tip of the indentation by testing the appearance of the indentation by using a scanning electron microscope, and only a stacking crack appears at the edge of the indentation, as shown in figure 2.

Example 2:

the same materials and methods as those of example 1 were used, which are different from those of example 1 in that, in the step 1) of mirror polishing and ultrasonic cleaning of the substrate, ultrasonic cleaning was carried out for 25 minutes; in the step 2), the vacuum degree of the deposition chamber is pumped to 2.7 multiplied by 10^-3Pa; step 3), in the deposition of the transition Cr layer, the pressure of working gas in a deposition cavity is kept at 0.12Pa, and the preparation temperature is 200 ℃; step 4), in the deposition of the CrN coating, the pressure of working gas in a deposition cavity is kept at 0.12Pa, and the preparation temperature is 200 ℃; step 5) in the deposition of the CrTiNiSiN coating, the pressure of working gas in a deposition cavity is kept at 0.12Pa, the preparation temperature is 200 ℃, and the CrNi target power is800W。

The sectional morphology scanning electron microscope image of the Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 2 is shown in FIG. 3.

The Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 2 had a Cr content of 60.7 at.%, a Ti content of 8.6 at.%, a Ni content of 9.7 at.%, a Si content of 1.4 at.%, and an N content of 19.5 at.%; the nano-hardness of the Cr/CrN/CrTiNiSiN multilayer nano-composite coating is 43.6GPa, the elastic modulus is 464.5GPa, and the coating has super-hard hardness; after the coating is pressed into the coating with the depth of 1 mu m by using a nano indentation large load, the appearance of the indentation is tested by using a scanning electron microscope, no crack is found, and as shown in figure 4, the coating has better toughness.

The coating has super-hard hardness and good toughness, so that the coating with both hard and tough properties is obtained, and the coating is suitable for being applied to a protective layer of a wear-resistant coating or a cutter coating.

Example 3:

the same materials and methods as those of example 1 were used, which are different from those of example 1 in that, in the step 1) of mirror polishing and ultrasonic cleaning of the substrate, ultrasonic cleaning was performed for 30 minutes; in step 2), the vacuum degree of the deposition chamber is pumped to 3.0 multiplied by 10^-3Pa; step 3), in the deposition of the transition Cr layer, the pressure of working gas in a deposition cavity is kept at 0.15Pa, and the preparation temperature is 250 ℃; step 4), in the deposition of the CrN coating, the pressure of working gas in a deposition cavity is kept at 0.15Pa, and the preparation temperature is 250 ℃; and step 5) keeping the pressure of working gas in a deposition cavity in the deposition of the CrTiNiSiN coating at 0.15Pa, wherein the preparation temperature is 250 ℃, and the CrNi target power is 1200W.

The sectional morphology scanning electron microscope image of the Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 3 is shown in FIG. 5.

The Cr/CrN/CrTiNiSiN multilayer nanocomposite coating prepared in example 3 had a Cr content of 57.1 at.%, a Ti content of 7.8 at.%, a Ni content of 16.0 at.%, a Si content of 2.0 at.%, and an N content of 17.1 at.%; the nano-hardness of the Cr/CrN/CrTiNiSiN multilayer nano-composite coating is 38.3GPa, and the elastic modulus is 412.8 GPa; after the coating is pressed into the coating with the depth of 1 mu m by using a nano indentation large load, the shape of the indentation is tested by using a scanning electron microscope, and no crack is found, as shown in figure 6.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.