CN111962029A - A high temperature self-lubricating (Cr, V) 2AlC MAX phase coating and its preparation method and application - Google Patents

Abstract

The invention discloses a high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating and a preparation method and application thereof. The coating comprises a (Cr,V) ₂ AlC MAX phase and a small amount of impurity phases, the content of the (Cr, V) ₂ AlC MAX phase in the coating is greater than or equal to 90 wt %, and the coating has a close-packed hexagonal structure, Wherein MA layers with metallic properties alternate with MX layers with valence properties, where M is Cr and/or V, A is Al, and X is C. In the present invention, the surface modification of the Cr ₂ AlC coating is carried out through the solid solution of V element, which not only greatly improves the hardness and toughness of the coating due to the effect of solid solution strengthening and lattice distortion, but also generates V element at high temperature. The ₂ O ₅ Magnéli phase has good lubricating properties, so that the prepared coating has good high temperature wear resistance and lubricity; the method is simple, efficient, economical and environmentally friendly, and has good application value.

Description

A high temperature self-lubricating (Cr, V) 2AlC MAX phase coating and its preparation method and application

technical field

The invention belongs to the technical field of surface engineering protection, and in particular relates to a high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating and a preparation method and application thereof.

Background technique

The MAX phase is a class of ternary layered carbides and nitrides. These materials have both metallic and ceramic properties, such as excellent high-temperature oxidation resistance, thermal shock resistance, electrical conductivity and thermal conductivity. Among them, the Cr ₂ AlC MAX phase has a relatively matching thermal expansion coefficient with the high temperature nickel-based alloy. In the high temperature environment, the two elements of Cr and Al will form Cr ₂ O ₃ and Al ₂ O ₃ oxide films to provide protection and certain lubrication. . Based _on these characteristics, Cr2AlC is considered as one of the most promising candidates for medium/high temperature, strain-resistant, corrosion-resistant coatings for gas turbines, nuclear cladding or other applications in harsh environments.

However, the hardness of Cr ₂ AlC coating is low, and the protective Cr ₂ O ₃ and Al ₂ O ₃ oxide films have insufficient lubricity, and the hard oxide particles are easy to cause abrasive wear. In addition, the Al reserves of the Cr ₂ AlC coating are limited, and after the Al is consumed by oxygen, it will further react with other elements in the coating, resulting in the failure of the coating. The friction coefficient of Cr ₂ AlC coating is higher and its life is shorter, which affects its application in high temperature environment.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating and its preparation method and application, so as to overcome the deficiencies of the prior art.

In order to realize the foregoing invention purpose, the technical scheme adopted in the present invention includes:

An embodiment of the present invention provides a high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating, the coating comprising a (Cr, V) ₂ AlC MAX phase and a small amount of impurity phase, in the coating (Cr, V) 2 AlC MAX phase V) The content of ₂ AlC MAX phase is more than 90wt%, the coating has a close-packed hexagonal structure, wherein the coating comprises alternating MA layers with metallic properties and MX layers with covalent properties, the M is Cr and/or V, A is Al, X is C, and a small amount of impurity phase is dispersed in the (Cr,V) ₂ AlC MAX phase coating.

Embodiments of the present invention also provide a method for preparing the aforementioned high-temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating, which includes:

provide a base;

A Cr-V-Al-C as-deposited coating is deposited on the surface of the substrate by arc ion plating composite magnetron sputtering technology;

And, in a vacuum environment, heat treatment is performed on the Cr-V-Al-C as-deposited coating to obtain a high-temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating.

The embodiments of the present invention also provide the use of the aforementioned high-temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating in the field of substrate surface protection in a high-temperature environment.

Compared with the prior art, the beneficial effect of the present invention is that: the present invention performs surface modification of the Cr ₂ AlC coating by solid solution of V element, not only due to the effects of solid solution strengthening and lattice distortion, but also greatly improves the coating. The hardness and toughness of Cr 2 AlC coating are high, and V element will generate V ₂ O ₅ Magnéli phase at high temperature, which has good lubricating properties, which solves the problems of insufficient Al reserves, too fast consumption and low lubricity of Cr ₂ AlC coating; The coating prepared by the invention has good high temperature wear resistance and lubricity; the method provided by the invention is simple, efficient, economical and environmentally friendly, and has good application value.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments described in this application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is the XRD pattern of (Cr, V) ₂ AlC MAX phase coating obtained in Example 1 of the present invention;

Fig. 2 is the surface topography of (Cr, V) ₂ AlC MAX phase coating obtained in Example 1 of the present invention;

Fig. 3 is the indentation topography of (Cr, V) ₂ AlC MAX phase coating obtained in Example 1 of the present invention;

Fig. 4 is the XRD pattern of (Cr, V) ₂ AlC MAX phase coating obtained in Example 2 of the present invention;

Fig. 5 is the surface topography of (Cr, V) ₂ AlC MAX phase coating obtained in Example 2 of the present invention;

Fig. 6 is the indentation topography of (Cr, V) ₂ AlC MAX phase coating obtained in Example 2 of the present invention;

Fig. 7 is the XRD pattern of (Cr, V) ₂ AlC MAX phase coating obtained in Example 3 of the present invention;

Fig. 8 is the surface topography of (Cr, V) ₂ AlC MAX phase coating obtained in Example 3 of the present invention;

Fig. 9 is the indentation topography of (Cr, V) ₂ AlC MAX phase coating obtained in Example 3 of the present invention;

10 is the XRD pattern of the Cr ₂ AlC MAX phase coating obtained in Comparative Example 1 of the present invention;

Fig. 11 is the surface topography of the Cr ₂ AlC MAX phase coating obtained in Comparative Example 1 of the present invention;

Fig. 12 is the indentation topography of the Cr ₂ AlC MAX phase coating obtained in Comparative Example 1 of the present invention;

13 is the XRD pattern of the (Cr,V) ₂ AlC MAX phase coating obtained in Comparative Example 2 of the present invention;

Fig. 14 is the surface topography of (Cr, V) ₂ AlC MAX phase coating obtained in Comparative Example 2 of the present invention;

Figure 15 is an indentation topography of the (Cr,V) ₂ AlC MAX phase coating obtained in Comparative Example 2 of the present invention;

16 is the XRD pattern of the (Cr,V) ₂ AlC MAX phase coating obtained in Comparative Example 3 of the present invention;

Fig. 17 is the surface topography of (Cr, V) ₂ AlC MAX phase coating obtained in Comparative Example 3 of the present invention;

Figure 18 is an indentation topography of the (Cr,V) ₂ AlC MAX phase coating obtained in Comparative Example 3 of the present invention;

Figure 19 is a hardness histogram of Example 1-3 and Comparative Example 1-3 of the present invention;

FIG. 20 is a histogram of friction coefficients of Examples 1-3 and Comparative Examples 1-3 of the present invention.

Detailed ways

In view of the defects of the prior art, after long-term research and a lot of practice, the inventor of the present case was able to propose the technical solution of the present invention, which is mainly to modify the surface of the Cr ₂ AlC coating through the solid solution of V element to obtain high-temperature self-lubricating (Cr 2 AlC) coating. , V) ₂ AlCMAX phase coating.

The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

One aspect of the embodiments of the present invention provides a high temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating, the coating comprising a (Cr, V) ₂ AlC MAX phase and a small amount of impurity phase, in the coating The content of the (Cr,V) ₂ AlC MAX phase is above 90 wt %, the coating has a close-packed hexagonal structure, wherein the coating comprises alternating MA layers with metallic properties and MX layers with covalent properties, The M is Cr and/or V, A is Al, X is C, and a small amount of impurity phase is dispersed and distributed.

In the high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating prepared by the invention, from the atomic level, the structure of the MAX phase coating is a structure in which MA layers and MX layers are alternately arranged, and the MAX phase coating has both Has both metal and ceramic properties, such as good thermal conductivity and oxidation resistance.

In some specific embodiments, the impurity phase has multiple phases, and the impurity phase includes any one or two of a Cr phase, a Cr ₂ Al phase, a Cr ₅ Al ₈ phase, and an intermetallic compound A combination of the above, but not limited to this.

Further, the impurity phase is dispersed and distributed in the (Cr,V) ₂ AlC MAX phase coating.

Further, the thickness of the high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating is 6-10 μm.

Another aspect of the embodiments of the present invention also provides a method for preparing the aforementioned high-temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating, comprising:

provide a base;

A Cr-V-Al-C as-deposited coating is deposited on the surface of the substrate by arc ion plating composite magnetron sputtering technology;

And, in a vacuum environment, heat treatment is performed on the Cr-V-Al-C as-deposited coating to obtain a high-temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating.

In the present invention, the Cr-V-Al-C as-deposited coating deposited on the substrate is in an amorphous state, and a crystal, ie, a high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating, will be formed after heat treatment.

In some specific embodiments, the preparation method includes: using arc ion plating composite magnetron sputtering technology, using a Cr/V alloy target as the arc source target, and using an Al target as the magnetron sputtering target to protect the The reactive gas and the carbon source gas are used as working gases, and a bias voltage is applied to the substrate, thereby depositing a Cr-V-Al-C deposited coating on the surface of the substrate; wherein the deposition time is 1-5 h, and the temperature is 100-350 °C.

Further, the current of the arc source target is 50-70A, the power is 0.8-1.1kw, and the atomic ratio of Cr to V in the Cr/V alloy target material is 1:0-1:1.

Further, the current of the magnetron sputtering target is 7-10A, and the power is 2.8-3.2kw.

Further, the bias voltage of the substrate is -100--200V.

Further, the carbon source gas includes acetylene or methane.

Further, the flow rate of the carbon source gas is 15-50 sccm.

Further, the protective gas is argon.

Further, the gas pressure of the working gas is 10-20 mTorr.

In some more specific embodiments, the preparation method includes: in a vacuum environment, the Cr-V-Al-C as-deposited coating is heat-treated at 500-750° C. for 30-120 minutes to obtain the high temperature Self-lubricating (Cr,V) ₂ AlCMAX phase coating.

Further, the vacuum degree of the vacuum environment is less than 3.0×10 ^-5 Torr.

In some specific embodiments, the preparation method further includes: cleaning and etching the substrate surface before depositing the Cr-V-Al-C as-deposited coating on the substrate surface.

Further, the cleaning includes: degreasing and cleaning the surface of the substrate with a metal cleaning agent.

Further, the etching treatment includes: placing the substrate in a vacuum chamber with a temperature of 100-350° C., introducing an inert gas, applying a bias voltage of -150--300V to the substrate, and performing Ar ion etching on the substrate. Eclipse 20 ~ 50min.

In some specific embodiments, the thickness of the high temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating is 6-10 μm.

Further, the substrate includes a superalloy, but is not limited thereto.

In some more specific embodiments, the preparation method comprises:

(1) Degrease and clean the surface of the superalloy substrate with a metal cleaning agent;

(2) using Ar ion etching method to etch the superalloy at 200°C for 20min-50min;

(3) Preparation of Cr-V-Al-C as-deposited coating by arc ion plating composite magnetron sputtering technology;

(4) Heat treatment of the Cr-V-Al-C as-deposited coating in a vacuum environment to obtain a (Cr,V) ₂ AlC MAX phase coating.

Another aspect of the embodiments of the present invention also provides the use of the aforementioned high-temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating in the field of substrate surface protection in a high-temperature environment.

Aiming at the deficiencies of the hardness, high temperature wear resistance and lubricity of the Cr ₂ AlC coating, the invention provides a simple, efficient, economical and environmentally friendly high temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating and a preparation method thereof. The surface modification of the Cr ₂ AlC coating by the solid solution of V element can improve the hardness and toughness of the coating due to the effect of solid solution strengthening and lattice distortion, and on the other hand, V element will generate V ₂ O at high temperature The ₅ Magnéli phase has good lubricating properties, combined with the excellent high temperature oxidation resistance of the Cr ₂ AlC coating, which makes the coating have good high temperature wear resistance and lubricity. The technical solution of the present invention will be described in further detail below with reference to several preferred embodiments and accompanying drawings. The scope of protection is not limited to the following examples.

The experimental materials used in the following examples can be purchased from conventional biochemical reagent companies unless otherwise specified.

Example 1

In the present embodiment, the (Cr, V) ₂ AlC MAX phase coating is obtained by arc ion plating composite magnetron sputtering technology, and the specific process is as follows:

(1) Put the superalloy substrate after cleaning, degreasing and drying into the cavity;

(2) When the vacuum pressure in the chamber is below 3.0×10 ^-5 Torr, set the temperature to 200°C, pass Ar gas of 35sccm into the vacuum chamber, set the linear anode ion source current to 0.20A, and set the substrate bias to -200V , the substrate was etched with ionized argon ions for 30 min.

(3) In an Ar protective atmosphere of 200sccm, the temperature is 200℃, a Cr/V alloy target is installed on the arc source, the atomic ratio of Cr/V is 1/1, and the target power is 1.0kw for the deposition of Cr-V. , the current is 60A. The magnetron source is an Al target, the target power is 3.0kw, and the current is 8.2A. The substrate bias was set to -150V, 30sccm of CH ₄ was passed through, the gas pressure in the cavity was 15 mTorr, and the deposition was performed for 3 hours to obtain the deposited Cr-V-Al-C coating;

(4) The obtained as-deposited Cr-V-Al-C coating was placed in an annealing furnace, and kept at 700 °C for 90 min in an environment with a vacuum degree lower than 3.0×10 ^-5 Torr to obtain (Cr, V ) ₂ AlC MAX phase coating;

(5) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was placed in a high temperature friction machine under the conditions of a speed of 1cm/s, a friction distance of 20m, a friction radius of 5mm and a temperature of 900°C High temperature friction test under high temperature;

(6) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was subjected to an indentation test under a load of 300 g;

(7) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was subjected to nanoindentation test under the conditions of a depth of 1500 nm and a Poisson's ratio of 0.2, and the hardness value of the coating was calculated;

The XRD pattern of the solid solution (Cr, V) ₂ AlC MAX phase coating after the above heat treatment is shown in Figure 1. It can be seen that the composition of the coating is composed of (Cr, V) ₂ AlC and Cr two phases, which are determined by XRD Rietveld The refinement results show that the (Cr,V) ₂ AlC phase content is 92 wt %, and the Cr phase content is 8 wt %. The surface topography of the above (Cr, V) ₂ AlC MAX phase coating is shown in Figure 2, which shows that the coating is dense and free of defects, and there are large particles produced by sputtering on the surface of the coating, with a roughness of 188 nm. The indentation morphology of the above (Cr,V) ₂ AlC MAX phase coating is shown in Figure 3, which shows that the indentation is shallow and no cracks are observed around it, indicating that the coating has good toughness. The hardness value obtained by the nanoindentation test was 22.310 GPa (see Figure 19). At 900°C, the coefficient of friction (COF) curve stabilized and averaged around 0.25 (see Figure 20).

Example 2:

In the present embodiment, the (Cr, V) ₂ AlC MAX phase coating is obtained by arc ion plating composite magnetron sputtering technology, and the specific process is as follows:

(1) Put the superalloy substrate after cleaning, degreasing and drying into the cavity;

(2) When the vacuum pressure in the chamber is below 3.0×10 ^-5 Torr, set the temperature to 200°C, pass Ar gas of 35sccm into the vacuum chamber, set the linear anode ion source current to 0.20A, and set the substrate bias to -200V , using ionized argon ions to etch the substrate for 30min;

(3) In the Ar protective atmosphere of 200sccm, the temperature is 200℃, the Cr/V alloy target is installed on the arc source, the atomic ratio of Cr/V is 3/1, it is used to deposit Cr-V, and the target power is 1.0kw , the current is 60A. The magnetron source is an Al target, the target power is 3.0kw, and the current is 8.2A. The substrate bias was set to -150V, 15sccm of CH ₄ was passed through, the gas pressure in the cavity was 15 mTorr, and the deposition was performed for 3 hours to obtain the deposited Cr-V-Al-C coating;

(4) The obtained as-deposited Cr-V-Al-C coating was placed in an annealing furnace, and kept at 550 °C for 90 min in an environment with a vacuum degree lower than 3.0×10 ^-5 Torr to obtain (Cr, V ) ₂ AlC MAX phase coating;

(5) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was placed in a high temperature friction machine, under the conditions of a speed of 1cm/s, a friction distance of 20m, a friction radius of 5mm, and a temperature of 800°C High temperature friction test under high temperature;

(6) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was subjected to an indentation test under a load of 300 g;

(7) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was subjected to nanoindentation test under the conditions of a depth of 1500 nm and a Poisson's ratio of 0.2, and the hardness value of the coating was calculated;

The XRD pattern of the solid solution (Cr, V) ₂ AlC MAX phase coating after the above heat treatment is shown in Figure 4. It can be seen that the composition of the coating is composed of (Cr, V) ₂ AlC and Cr two phases, which is determined by XRD Rietveld The refinement results show that the (Cr,V) ₂ AlC phase content is 92 wt %, and the Cr phase content is 8 wt %. The surface topography of the above (Cr,V) ₂ AlC MAX phase coating is shown in Figure 5, which shows that the coating is dense and free of defects, and there are large particles produced by sputtering on the surface of the coating, with a roughness of 124 nm. The indentation morphology of the above (Cr,V) ₂ AlC MAX phase coating is shown in Figure 6, which shows that a few cracks can be observed around the indentation, indicating that the coating has good toughness. The hardness value obtained by the nanoindentation test was 19.773 GPa (see Figure 19). At 800°C, after the coefficient of friction (COF) curve stabilized, the average was around 0.31 (see Figure 20).

Example 3:

(1) Put the superalloy substrate after cleaning, degreasing and drying into the cavity;

(2) When the vacuum pressure in the chamber is below 3.0×10 ^-5 Torr, set the temperature to 200°C, pass Ar gas of 35sccm into the vacuum chamber, set the linear anode ion source current to 0.20A, and set the substrate bias to -200V , using ionized argon ions to etch the substrate for 30min;

(3) In the Ar protective atmosphere of 200sccm, the temperature is 200℃, the Cr/V alloy target is installed on the arc source, the atomic ratio of Cr/V is 2/1, and the target power is 1.0kw for the deposition of Cr-V. , the current is 60A. The magnetron source is an Al target, the target power is 3.0kw, and the current is 8.2A. The substrate bias was set to -150V, 50sccm of CH ₄ was fed, the gas pressure in the cavity was 15 mTorr, and the deposition was performed for 3 hours to obtain the deposited Cr-V-Al-C coating;

(4) The obtained as-deposited Cr-V-Al-C coating was placed in an annealing furnace, and kept at 600 °C for 90 min in an environment with a vacuum degree lower than 3.0×10 ^-5 Torr to obtain (Cr, V ) ₂ AlC MAX phase coating;

(5) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was placed in a high temperature friction machine, under the conditions of a speed of 1cm/s, a friction distance of 20m, a friction radius of 5mm, and a temperature of 800°C High temperature friction test under high temperature;

(6) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was subjected to an indentation test under a load of 300 g;

(7) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was subjected to nanoindentation test under the conditions of a depth of 1500 nm and a Poisson's ratio of 0.2, and the hardness value of the coating was calculated;

The XRD pattern of the solid solution (Cr,V) ₂ AlC MAX phase coating after the above heat treatment is shown in Figure 7. It can be seen that the composition of the coating is composed of (Cr, V) ₂ AlC and Cr ₂ Al two phases, consisting of XRD Rietveld refinement results show that the content of (Cr,V) ₂ AlC phase is 95 wt%, and the content of Cr ₂ Al phase is 5 wt%. The surface topography of the above (Cr,V) ₂ AlC MAX phase coating is shown in Figure 8, which shows that the coating is dense and free of defects, and there are large particles produced by sputtering on the surface of the coating, with a roughness of 150 nm. The indentation morphology of the above (Cr,V) ₂ AlCMAX phase coating is shown in Figure 9, which shows that no cracks are observed around the indentation, and the indentation is shallow, indicating that the coating has good toughness. The hardness value obtained by the nanoindentation test was 20.023 GPa (see Figure 19). At 700°C, the coefficient of friction (COF) curve stabilized and averaged around 0.32 (see Figure 20).

Example 4:

(1) Put the superalloy substrate after cleaning, degreasing and drying into the cavity;

(2) When the vacuum pressure in the chamber is below 3.0×10 ^-5 Torr, set the temperature to 100°C, pass Ar gas of 35sccm into the vacuum chamber, set the linear anode ion source current to 0.20A, and the substrate bias to -150V , using ionized argon ions to etch the substrate for 20min;

(3) In the Ar protective atmosphere of 200sccm, the temperature is 200℃, the Cr/V alloy target is installed on the arc source, the atomic ratio of Cr/V is 10/1, and the target power is 0.8kw for the deposition of Cr-V. , the current is 50A. The magnetron source is an Al target, the target power is 2.8kw, and the current is 7A. The substrate bias was set to -100V, 15sccm of CH ₄ was passed through, the gas pressure in the cavity was 10 mTorr, and the deposition was carried out for 5 hours to obtain the as-deposited Cr-V-Al-C coating;

(4) The obtained as-deposited Cr-V-Al-C coating was placed in an annealing furnace, and kept at 500°C for 120 min in an environment with a vacuum degree lower than 3.0×10 ^-5 Torr to obtain (Cr, V ) ₂ AlC MAX phase coating.

Example 5:

(1) Put the superalloy substrate after cleaning, degreasing and drying into the cavity;

(2) When the vacuum pressure in the chamber is below 3.0×10 ^-5 Torr, the temperature is set to 350°C, 35sccm of Ar gas is passed into the vacuum chamber, the linear anode ion source current is set to 0.20A, and the substrate bias voltage is -300V , using ionized argon ions to etch the substrate for 50min;

(3) In an Ar protective atmosphere of 200sccm, the temperature is 350℃, a Cr/V alloy target is installed on the arc source, and the atomic ratio of Cr/V is 20/1, which is used to deposit Cr-V, and the target power is 1.1kw , the current is 70A. The magnetron source is an Al target, the target power is 3.2kw, and the current is 10A. The substrate bias is set to -200V, 50sccm of CH ₄ is fed, the gas pressure in the cavity is 20mTorr, and the deposition is performed for 1h to obtain the deposited Cr-V-Al-C coating;

(4) The obtained as-deposited Cr-V-Al-C coating was placed in an annealing furnace, and kept at 750 °C for 30 min in an environment with a vacuum degree lower than 3.0×10 ^-5 Torr to obtain (Cr, V ) ₂ AlC MAX phase coating.

Comparative Example 1:

This example is a comparative example of Example 2.

In this embodiment, Cr is used as the arc source, and the other conditions are exactly the same as those in the above-mentioned embodiment 2 to prepare the (Cr, V) ₂ AlC MAX phase coating, that is, to prepare the Cr ₂ AlC MAX phase coating that does not contain V element, The specific process is as follows:

(1) Put the superalloy substrate after cleaning, degreasing and drying into the cavity;

(2) When the vacuum pressure in the chamber is below 3.0×10 ^-5 Torr, set the temperature to 200°C, pass Ar gas of 35sccm into the vacuum chamber, set the linear anode ion source current to 0.20A, and set the substrate bias to -200V , using ionized argon ions to etch the substrate for 30min;

(3) In a 200sccm Ar protective atmosphere, the temperature is 200°C, a Cr metal target is installed on the arc source, the target power is 1.0kw, and the current is 60A. The magnetron source is an Al target, the target power is 3.0kw, and the current is 8.2A. The substrate bias was set to -150V, 15sccm of CH ₄ was passed through, the air pressure in the cavity was 15 mTorr, and the deposition was performed for 3 hours to obtain the as-deposited Cr-Al-C coating;

(4) placing the obtained as-deposited CrAl-C coating in an annealing furnace, in an environment where the vacuum degree is lower than 3.0×10 ^-5 Torr, and keeping the temperature at 550°C for 90 minutes to obtain a Cr ₂ AlC MAX phase coating;

(5) The annealed solid solution Cr ₂ AlC MAX phase coating was placed in a high temperature friction machine, and the high temperature friction was carried out under the conditions of a speed of 1 cm/s, a friction distance of 20 m, a friction radius of 5 mm, and a temperature of 800 °C test;

(6) The annealed solid solution Cr ₂ AlC MAX phase coating is subjected to an indentation test under a load of 300 g;

(7) The annealed solid solution Cr ₂ AlC MAX phase coating is subjected to nanoindentation test under the conditions of a depth of 1500 nm and a Poisson's ratio of 0.2, and the hardness value of the coating is calculated;

The XRD pattern of the solid solution Cr ₂ AlC MAX phase coating after the above heat treatment is shown in Figure 10. It can be seen that the composition of the coating is composed of Cr ₂ AlC and Cr two phases. According to the XRD Rietveld refinement results, Cr ₂ AlC The phase content was 90 wt%, and the Cr phase content was 10 wt%. The surface topography of the above Cr ₂ AlC MAX phase coating is shown in Figure 11, which shows that the coating is dense and free of defects, and there are a small amount of large particles produced by sputtering on the surface of the coating, with a roughness of 22.1 nm. The indentation morphology of the above Cr ₂ AlC MAX phase coating is shown in Figure 12, which shows that obvious cracks can be observed around the indentation, indicating that the coating has poor toughness. The hardness value obtained by nanoindentation test was 16.627GPa (see Figure 19). At 800°C, after the coefficient of friction (COF) curve stabilized, the average was around 0.57 (see Figure 20).

Comparative Example 2:

This example is a comparative example of the above-mentioned Example 1.

In this example, the annealing temperature is 400°C, and other conditions are the same as those in Example 1 to prepare the (Cr,V) ₂ AlC MAX phase coating. The specific process is as follows:

(1) Put the superalloy substrate after cleaning, degreasing and drying into the cavity;

(2) When the vacuum pressure in the chamber is below 3.0×10 ^-5 Torr, set the temperature to 200°C, pass Ar gas of 35sccm into the vacuum chamber, set the linear anode ion source current to 0.20A, and set the substrate bias to -200V , using ionized argon ions to etch the substrate for 30min;

(3) In an Ar protective atmosphere of 200sccm, the temperature is 200℃, a Cr/V alloy target is installed on the arc source, the atomic ratio of Cr/V is 1/1, and the target power is 1.0kw for the deposition of Cr-V. , the current is 60A. The magnetron source is an Al target, the target power is 3.0kw, and the current is 8.2A. The substrate bias was set to -150V, 30sccm of CH ₄ was passed through, the gas pressure in the cavity was 15 mTorr, and the deposition was performed for 3 hours to obtain the deposited Cr-V-Al-C coating;

(4) The obtained as-deposited Cr-V-Al-C coating was placed in an annealing furnace, and kept at 400 °C for 90 min in an environment with a vacuum degree lower than 3.0×10 ^-5 Torr to obtain (Cr, V ) ₂ AlC MAX phase coating;

(5) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was placed in a high temperature friction machine under the conditions of a speed of 1cm/s, a friction distance of 20m, a friction radius of 5mm and a temperature of 900°C High temperature friction test under high temperature;

(6) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was subjected to an indentation test under a load of 300 g;

(7) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was subjected to nanoindentation test under the conditions of a depth of 1500 nm and a Poisson's ratio of 0.2, and the hardness value of the coating was calculated;

The XRD pattern of the solid solution (Cr, V) ₂ AlC MAX phase coating after the above heat treatment is shown in Figure 13. It can be seen that the XRD pattern is relatively diffuse, with only some diffraction peaks of the substrate, and no (Cr, V) ₂ is observed. Diffraction peaks of the AlC MAX phase. The surface topography of the above coating is shown in Figure 14, which shows that the coating is dense and free of defects, there are large particles produced by sputtering on the surface of the coating, and the roughness is 192 nm. The indentation morphologies of the above coatings are shown in Figure 15, showing that obvious cracks can be observed around the indentation. The hardness value obtained by the nanoindentation test was 17.223 GPa (see Figure 19). At 900°C, after the coefficient of friction (COF) curve stabilized, the average was around 0.42 (see Figure 20).

Comparative Example 3:

This example is another comparative example of Example 1.

In this example, the flow rate of CH ₄ is 10sccm, and other conditions are the same as those in Example 1 to prepare the (Cr, V) ₂ AlC MAX phase coating. The specific process is as follows:

(1) Put the superalloy substrate after cleaning, degreasing and drying into the cavity;

(2) When the vacuum pressure in the chamber is below 3.0×10 ^-5 Torr, set the temperature to 200°C, pass Ar gas of 35sccm into the vacuum chamber, set the linear anode ion source current to 0.20A, and set the substrate bias to -200V , using ionized argon ions to etch the substrate for 30min;

(3) In an Ar protective atmosphere of 200sccm, the temperature is 200℃, a Cr/V alloy target is installed on the arc source, the atomic ratio of Cr/V is 1/1, and the target power is 1.0kw for the deposition of Cr-V. , the current is 60A. The magnetron source is an Al target, the target power is 3.0kw, and the current is 60A. The substrate bias was set to -150V, 10sccm of CH ₄ was passed through, the gas pressure in the cavity was 15mTorr, and the deposition was performed for 3h to obtain the as-deposited Cr-V-Al-C coating;

(4) The obtained as-deposited Cr-V-Al-C coating was placed in an annealing furnace, and kept at 700 °C for 90 min in an environment with a vacuum degree lower than 3.0×10 ^-5 Torr to obtain (Cr, V ) ₂ AlC MAX phase coating;

(5) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was placed in a high temperature friction machine under the conditions of a speed of 1cm/s, a friction distance of 20m, a friction radius of 5mm and a temperature of 900°C High temperature friction test under high temperature;

(6) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating is subjected to an indentation test under a load of 300 g.

(7) The annealed solid solution (Cr, V) ₂ AlC MAX phase coating was subjected to nanoindentation test under the conditions of a depth of 1500 nm and a Poisson's ratio of 0.2, and the hardness value of the coating was calculated;

The XRD pattern of the solid solution (Cr,V) ₂ AlC MAX phase coating after the above heat treatment is shown in Figure 16. It can be seen that the coating has a crystalline phase, but not a (Cr, V) ₂ AlC phase. The surface topography of the above coating is shown in Figure 17, which shows that the coating is dense and free of defects, and there are large particles produced by sputtering on the surface of the coating, with a roughness of 180 nm. The indentation morphology of the above coating is shown in Figure 18, which shows that obvious cracks can be observed around the indentation, indicating that the coating has poor toughness. The hardness value obtained by nanoindentation test was 16.827GPa (see Figure 19). At 900°C, the coefficient of friction (COF) curve stabilized and averaged around 0.53 (see Figure 20).

In addition, the inventors of the present application also carried out experiments with other raw materials, technological operations and technological conditions mentioned in this specification with reference to the foregoing examples, and all obtained satisfactory results.

The aspects, embodiments, features, and examples of the present invention are to be considered in all respects illustrative and not intended to limit the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

The use of headings and sections in this application is not meant to limit the invention; each section is applicable to any aspect, embodiment or feature of the invention.

Throughout this specification, where a composition is described as having, comprising or including particular components, or where a process is described as having, comprising or including particular process steps, it is contemplated that the compositions of the present teachings will also be substantially The above consists of or consists of the recited components, and the processes taught herein also consist essentially of, or consist of, the recited process steps.

It should be understood that the order of the steps or the order in which the particular actions are performed is not critical so long as the present teachings remain operable. Furthermore, two or more steps or actions may be performed simultaneously.

Although the present invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions and/or additions and the like may be made without departing from the spirit and scope of the invention Effects replace elements of the described embodiments. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is not intended herein to limit the invention to the particular embodiments disclosed for carrying out the invention, but it is intended that this invention include all embodiments falling within the scope of the appended claims. Furthermore, unless specifically stated, any use of the terms first, second, etc. does not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.

Claims (10)

1. A high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating, characterized in that the coating comprises (Cr, V) ₂ AlC MAX phase and a small amount of impurity phase, and (Cr, V) 2 AlC MAX phase in the coating V) The content of ₂ AlC MAX phase is more than 90wt%, the coating has a close-packed hexagonal structure, wherein the coating comprises alternating MA layers with metallic properties and MX layers with covalent properties, M is Cr and/or V, A is Al, and X is C. 2. The high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating according to claim 1, wherein the impurity phase comprises any one of Cr phase, Cr ₂ Al phase, and Cr ₅ Al ₈ phase one or a combination of two or more; preferably, the impurity phase is dispersed and distributed in the (Cr, V) ₂ AlC MAX phase coating; And/or, the thickness of the high-temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating is 6-10 μm. 3. The preparation method of the high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating according to any one of claims 1-2, characterized in that it comprises: provide a base; A Cr-V-Al-C as-deposited coating is deposited on the surface of the substrate by arc ion plating composite magnetron sputtering technology; And, in a vacuum state, heat treatment is performed on the Cr-V-Al-C as-deposited coating to obtain a high-temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating. 4. The preparation method according to claim 3, characterized in that it comprises: adopting arc ion plating composite magnetron sputtering technology, using Cr/V alloy target material as the arc source target, and using the Al target as the magnetron sputtering target, Using the protective gas and the carbon source gas as the working gas, a bias voltage is applied to the substrate, thereby depositing a Cr-V-Al-C deposition coating on the surface of the substrate; wherein the deposition time is 1-5h, and the temperature is 100- 350°C. 5 . The preparation method according to claim 4 , wherein the current of the arc source target is 50-70A, the power is 0.8-1.1kw, and the atomic ratio of Cr to V in the Cr/V alloy target material is 5 . 1:0～1:1; And/or, the current of the magnetron sputtering target is 7-10A, and the power is 2.8-3.2kw. 6 . The preparation method according to claim 4 , wherein the bias voltage of the substrate is -100～-200V; 6 . And/or, the carbon source gas includes acetylene and/or methane; preferably, the flow rate of the carbon source gas is 15-50 sccm; and/or, the protective gas includes argon; And/or, the gas pressure of the working gas is 10-20 mTorr. 7. The preparation method according to claim 3, characterized by comprising: in a vacuum environment, the Cr-V-Al-C deposited coating is heat-treated at 500-750 DEG C for 30-120min to obtain a solid solution obtained by solid solution. The high temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating; Preferably, the vacuum degree of the vacuum environment is less than 3.0×10 ^-5 Torr. 8. The preparation method according to claim 3, further comprising: prior to depositing the Cr-V-Al-C deposition coating on the substrate surface, firstly cleaning and etching the substrate surface; Preferably, the cleaning includes: degreasing and cleaning the surface of the substrate with a metal cleaning agent; preferably, the etching treatment includes: placing the substrate in a vacuum chamber with a temperature of 100-350° C., and pouring argon into it. gas, a bias voltage of -150--300V is applied to the substrate, and Ar ion etching is performed on the substrate for 20-50 minutes. 9 . The preparation method according to claim 3 , wherein the thickness of the high-temperature self-lubricating (Cr, V) ₂ AlC MAX phase coating is 6-10 μm; 10 . And/or, the substrate includes a superalloy. 10. The use of the high-temperature self-lubricating (Cr,V) ₂ AlC MAX phase coating described in claim 1 or 2 in the field of substrate surface protection in high-temperature environments.

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