Multi-component carbide coating capable of resisting oxidation and abrasion at high temperature and preparation method of multi-component carbide coating

Abstract

The invention discloses a multi-element carbide coating resistant to oxidation and abrasion at high temperature and a preparation method thereof. The coating is composed of a CrY / CrYTiAl composite transition layer and a (TiCrNbAlY) C functional layer, the atomic percent of the C element in the functional layer is 40%-60%, and the atomic percent of the five metal elements of Ti, Cr, Nb, Al and Y is 5%-12%. A multi-arc ion plating technology is adopted for preparation, argon is firstly introduced to deposit the composite transition layer, and then acetylene and argon are introduced to deposit the functional layer. The thermal stress between the substrate and the coating is effectively relieved through the composite transition layer, and the bonding strength is improved; the functional layer can form a compact amorphous oxide layer and a single-phase high-entropy oxide layer at high temperature, oxygen diffusion is remarkably hindered, cracks are avoided, meanwhile, the oxide layer plays a solid lubrication role in the friction process, and excellent high-temperature oxidation resistance and wear resistance are shown. The coating is compact in structure, good in combination and suitable for various base materials such as stainless steel and high-temperature alloy, and has wide application prospects in surface protection of high-temperature components in the fields of aerospace, energy equipment and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vacuum coating and surface protective coating, and particularly relates to a high-temperature oxidation-resistant wear-resistant multi-element carbide coating and a preparation method thereof. BACKGROUND

[0002] With the rapid development of aerospace, energy power, high-end equipment manufacturing and other fields, various mechanical parts and power systems are facing increasingly severe working environments of high temperature, high pressure, high load and complex chemical medium coupling. Under such extreme conditions, the surface of metal structural materials (such as nickel-based high-temperature alloy, titanium alloy, stainless steel, etc.) is prone to high-temperature oxidation, hot corrosion and wear, resulting in distortion of part size, degradation of performance, and even early failure, which seriously restricts the reliability, life and safety of equipment.

[0003] To improve the service performance of key parts in high-temperature environment, surface protective coating technology is widely used. Among them, carbide ceramic coating (such as TiC, CrC, WC, etc.) has become an important choice in high-temperature protection field due to its high hardness, excellent wear resistance and good chemical stability. However, traditional single-element or binary carbide coatings still have obvious shortcomings in long-term high-temperature operation: first, the oxidation rate is fast at high temperature, and the protective oxidation film formation ability is limited; second, the oxidation film is prone to cracking or peeling, leading to continuous oxidation of the substrate; third, the coating is severely worn during high-temperature friction, and the wear resistance is insufficient.

[0004] In recent years, with the extension of the design concept of multi-principal-element high-entropy alloy, researchers have begun to try to introduce multi-element strategy into ceramic coating system and develop multi-element carbide, nitride and other high-entropy ceramic coatings. This kind of material, with its high-entropy effect, lattice distortion effect and slow diffusion effect, shows significant advantages in mechanical properties, thermal stability and corrosion resistance. However, the systematic study of multi-element carbide coating in high-temperature oxidation resistance is still relatively lacking, especially how to realize effective control of oxidation kinetics through element matching and microstructure design, which is still a technical difficulty in this field.

[0005] In addition, the mismatch of thermal expansion coefficient between the coating and the substrate often leads to high stress at the interface, which in turn causes the coating to crack or peel off. Therefore, designing a reasonable transition layer structure to relieve stress and enhance adhesion is also a key to achieving high-temperature long-life protection.

[0006] In summary, it is of great engineering significance and scientific value to develop a multi-element carbide coating with excellent high-temperature oxidation resistance, wear resistance and good interface compatibility, and to support a mature and reliable preparation process to improve the service ability of high-end equipment in extreme environments SUMMARY

[0007] The purpose of this invention is to overcome the shortcomings of existing carbide coatings in terms of insufficient oxidation resistance and wear resistance under high temperature conditions, and to provide a multi-component carbide coating with excellent high temperature stability, oxidation resistance and wear resistance, and a controllable preparation method thereof.

[0008] This invention is achieved using the following technical solution: A high-temperature oxidation-resistant and wear-resistant multi-element carbide coating comprises a CrY / CrYTiAl composite transition layer and a (TiCrNbAlY)C functional layer. The CrY / CrYTiAl composite transition layer is a gradient composite layer dominated by Cr, Y, Ti, and Al elements, deposited using one or more of Cr, Y, CrY alloy, TiAl alloy, and Ti targets through sequential or co-sputtering. The (TiCrNbAlY)C functional layer is a multi-element carbide layer dominated by Ti, Cr, Nb, Al, Y, and C elements, deposited in an acetylene atmosphere using one or more of Ti, Cr, Nb, TiAl alloy, and CrY alloy targets through reactive sputtering. It possesses a single face-centered cubic rock salt structure, with each metal element entering the cation sublattice sites of the TiC lattice to form a substitutional solid solution.

[0009] In the functional layer, the atomic percentage of carbon is 40%–60%, and the atomic percentages of metallic elements Ti, Cr, Nb, Al, and Y are controlled between 5% and 12%, respectively. The thickness of the composite transition layer is 50–500 nm, and the thickness of the functional layer is 1–5 μm.

[0010] The method for preparing the coating includes the following steps: 1) A multi-arc ion plating equipment was used to deposit a CrY / CrYTiAl composite transition layer on the surface of a metal substrate that had been cleaned with Ar ions. The process parameters were as follows: sputtering gas was Ar, chamber pressure was 0.4~0.8 Pa, arc target current was 50~100 A, substrate bias voltage was -100~-400 V, temperature was 150~350 ℃, and the target was turned on in the order of Cr, Y, CrY, TiAl, Ti with a time interval of 0~8 min. 2) Continue to deposit the (TiCrNbAlY)C functional layer on the transition layer, introduce the reactive gas C2H2 with a flow ratio of (0.5~2):1 to Ar, chamber pressure of 0.3~0.9 Pa, arc target current of 50~130 A, and introduce the Nb target. Other process parameters are consistent with the transition layer deposition stage.

[0011] The coating described in this invention is applicable to most metal substrates, such as 304 stainless steel, 9Cr18 stainless steel, Inconel 718 alloy, TC4 alloy, aluminum, copper and other soft metals and their alloys.

[0012] The present invention has the following beneficial effects: 1. By designing a CrY / CrYTiAl composite transition layer, stress concentration caused by the difference in thermal expansion coefficients between the substrate and the functional layer is effectively alleviated, significantly improving the coating bonding strength and thermal shock resistance. The multi-component carbide solid solution formed by the multi-metal elements (Ti, Cr, Nb, Al, Y) and C in the functional layer promotes the formation of a single rock salt structure through the high entropy effect, enhancing the high-temperature stability of the coating. The addition of elements such as Al, Y, and Cr promotes the formation of a dense and continuous amorphous oxide film at high temperatures, effectively blocking oxygen diffusion. In the later stage, a single-phase high-entropy oxide layer is formed, avoiding the generation of multi-phase interface cracks and greatly improving the oxidation resistance. During high-temperature friction, the surface oxide acts as a solid lubricant, undergoing periodic formation-consumption-regeneration, which stabilizes the friction coefficient, significantly reduces the wear rate, and exhibits excellent wear resistance. 2. The process of this invention has strong compatibility and can achieve high-performance coating preparation on a variety of substrates such as stainless steel, high-temperature alloys, and titanium alloys. It is suitable for surface protection of high-temperature moving parts such as aero-engine blades, gas turbine components, and nuclear reactor components. 3. The coating structure of this invention is dense and well-bonded, and it still has excellent anti-oxidation and anti-wear properties at a high temperature of 800℃, which has significant engineering application value. Attached Figure Description

[0013] Figure 1 The cross-sectional morphology of the high-temperature antioxidant and wear-resistant multi-component carbide coating is shown.

[0014] Figure 2 The XRD diffraction pattern of the oxidation-resistant and wear-resistant multi-component carbide coating at high temperature.

[0015] Figure 3 The cross-sectional morphology of the high-temperature antioxidant and wear-resistant multi-component carbide coating after high-temperature oxidation at 800℃ for 120 min is shown.

[0016] Figure 4 The friction coefficient curve of the anti-oxidation and wear-resistant multi-component carbide coating at high temperature is shown in the high-temperature friction process at 800℃.

[0017] Figure 5 The EDS energy spectrum and elemental content of the functional layer in the high-temperature antioxidant and wear-resistant multi-component carbide coating are obtained. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0019] I. Coating Preparation Example 1 1) A CrY / CrYTiAl composite transition layer was deposited on the surface of a 304 stainless steel substrate after Ar ion cleaning using a multi-arc ion plating system.

[0020] The cleaned 304 stainless steel substrate was placed in the deposition chamber. After evacuation, the sample was cleaned with Ar plasma for 20 minutes. Then, the Ar gas flow rate was adjusted to bring the chamber pressure to 0.5 Pa. After the chamber pressure stabilized, the arc target was activated to begin depositing the CrY / CrYTiAl composite transition layer. The Cr and Y targets were activated simultaneously initially, followed by a 2-minute interval before activating the TiAl and Ti targets simultaneously. The currents for each cathode arc target were 60 A for Cr, 60 A for Y, 90 A for TiAl, and 70 A for Ti. The negative bias voltage applied to the substrate during the deposition process, including the subsequent functional layer deposition, was -400 V; the chamber temperature was set to 200 °C.

[0021] 2) Following step 1), keeping the above conditions unchanged, turn on the reaction gas source C2H2 and Nb target, and continue to deposit a multi-component carbide (TiCrNbAlY)C functional layer on the surface of the transition layer; After depositing the CrY / CrYTiAl composite transition layer for 4 min, the reactive gas source C2H2 and the Nb target were turned on to begin depositing the (TiCrNbAlY)C functional layer. The flow ratio of reactive gas C2H2 to inert gas Ar was controlled at 2:1, and the chamber pressure was 0.9 Pa. Other arc target currents remained unchanged, and the Nb target current was set to 130 A. After 1 h of deposition, the deposition system was turned off, and the sample was removed from the chamber after cooling to room temperature.

[0022] Example 2 1) A CrY / CrYTiAl composite transition layer was deposited on the surface of an Inconel 718 substrate after Ar ion cleaning using a multi-arc ion plating system.

[0023] The cleaned Inconel 718 substrate was placed in the deposition chamber. After evacuation, the sample was cleaned with Ar ions for 20 minutes. Then, the Ar gas flow rate was adjusted to bring the chamber pressure to 0.5 Pa. Once the chamber pressure stabilized, the arc targets were activated to begin depositing the CrY / CrYTiAl composite transition layer. The CrY alloy target was activated first, followed by the TiAl target after a 4-minute interval. The currents for each cathode arc target were 70 A for CrY and 100 A for TiAl. The negative bias voltage applied to the substrate throughout the deposition process, including the subsequent functional layer deposition, was -200 V. The chamber temperature was set to 200 °C.

[0024] 2) Following step 1), keeping the above conditions unchanged, turn on the reaction gas source C2H2 and Nb target, and continue to deposit a multi-component carbide (TiCrNbAlY)C functional layer on the surface of the transition layer; After depositing the CrY / CrYTiAl composite transition layer for 8 min, the reactive gas source C2H2 and the Nb target were turned on to begin depositing the (TiCrNbAlY)C functional layer. The flow ratio of reactive gas C2H2 to inert gas Ar was controlled at 2:1, and the chamber pressure was 0.6 Pa. Other arc target currents remained unchanged, and the Nb target current was set to 125 A. After deposition for 1.5 h, the deposition system was turned off, and the sample was removed from the chamber after cooling to room temperature.

[0025] Example 3 1) A CrY / CrYTiAl composite transition layer was deposited on the surface of a 9Cr18 stainless steel substrate after Ar ion cleaning using a multi-arc ion plating system. The cleaned 9Cr18 stainless steel substrate was placed in the deposition chamber. After evacuation, the sample was cleaned with Ar ions for 20 minutes. Then, the Ar gas flow rate was adjusted to bring the chamber pressure to 0.5 Pa. Once the chamber pressure stabilized, the arc targets were activated to begin depositing the CrY / CrYTiAl composite transition layer. The Cr and Y targets were activated simultaneously initially, followed by a 5-minute interval before the TiAl and Ti targets were activated simultaneously. The currents for each cathode arc target were 70 A for Cr, 70 A for Y, 100 A for TiAl, and 80 A for Ti. The negative bias voltage applied to the substrate throughout the deposition process, including the subsequent functional layer deposition, was -100 V. The chamber temperature was set to 200 °C.

[0026] 2) Following step 1), keeping the above conditions unchanged, turn on the reaction gas source C2H2 and Nb target, and continue to deposit a multi-component carbide (TiCrNbAlY)C functional layer on the surface of the transition layer; After depositing the CrY / CrYTiAl composite transition layer for 10 min, the reactive gas source C2H2 and the Nb target were turned on to begin depositing the (TiCrNbAlY)C functional layer. The flow ratio of reactive gas C2H2 to inert gas Ar was controlled at 1.5:1, and the chamber pressure was 0.6 Pa. Other arc target currents remained unchanged, and the Nb target current was set to 125 A. After deposition for 2 h, the deposition system was turned off, and the sample was removed from the chamber after cooling to room temperature.

[0027] The following describes the structural characterization and performance evaluation of the sample prepared in Example 3.

[0028] II. Structural Characterization of Coatings The cross-sectional morphology of the coating was observed using ultra-high resolution field emission scanning electron microscopy (FE-SEM). For example... Figure 1As shown, the coating exhibits a clear dual-layer structure: a thin, dense CrY / CrYTiAl composite transition layer is located near the substrate, above which is a thicker (TiCrNbAlY)C functional layer. The two layers are tightly bonded together, with no visible cracks or pores, and the functional layer itself also has a very dense structure.

[0029] The phase structure of the coating was analyzed using X-ray diffraction (XRD). The results are as follows: Figure 2 As shown, the XRD pattern of the coating shows that it has a simple face-centered cubic (FCC) rock salt structure. All diffraction peaks can be attributed to the single solid solution phase of (Ti, Cr, Nb, Al, Y)C. No independent diffraction peaks of other carbide or metallic phases were found, indicating that the elements have successfully formed a multi-principal carbide solid solution.

[0030] Energy dispersive spectroscopy (EDS) was used to analyze the types and contents of elements in the coating. The results are as follows: Figure 5 As shown, the atomic percentages of each element in the (TiCrNbAlY)C functional layer are as follows: C 59.67%, Ti 8.58%, Cr 10.59%, Nb 8.43%, Al 9.18%, and Y 3.55%. The atomic percentages of all metal elements (Ti, Cr, Nb, Al, and Y) fall within the range of 5% to 12%, while the atomic percentage of C is within the range of 40% to 60%. This result clearly demonstrates that the elemental composition of the sample prepared in the examples fully conforms to the definition of the functional layer composition range in the claims, proving the controllability of the preparation process and the consistency of the coating composition.

[0031] III. Performance Evaluation of Coatings 1. High-temperature antioxidant performance test: The coated samples were placed in a muffle furnace and subjected to high-temperature oxidation experiments in air. The temperature was increased to the set temperature (700℃ or 800℃) at a rate of 5℃ / min and held for a certain time (e.g., 2 hours, 6 hours, 10 hours). After oxidation, the samples were cooled with the furnace. The thickness of the oxide layer on the cross-section of the coating was measured using scanning electron microscopy (SEM) to evaluate its oxidation resistance. Figure 3 As shown, after oxidation at 800℃ for 120 min, an extremely thin continuous oxide layer was formed on the coating surface, with an oxidation depth of only about 1.32 μm, indicating its excellent oxygen barrier ability. Oxidation depth data under different conditions are shown in Table 1.

[0032] Table 1 shows the oxide layer thickness of the coatings prepared in Examples 1-2 after high-temperature oxidation treatment under different conditions. 2. High-temperature friction and wear performance test: The wear resistance of the coating was evaluated using a high-temperature friction and wear testing machine in an atmospheric environment at 800℃. Al₂O₃ balls with a diameter of 6mm were selected as the grinding balls, a load of 2 N was applied, and the friction time was 60 min. The change in the coefficient of friction throughout the entire friction process was recorded. The results are as follows: Figure 4 As shown, the coefficient of friction exhibits obvious periodic fluctuations, eventually tending towards a stable equilibrium state, with a low average coefficient of friction. Calculations show that its wear rate is as low as 8.7 × 10⁻⁶. -6 mm 3 / (N•m) indicates that the coating has excellent wear resistance at high temperatures. Its wear resistance mechanism lies in the periodic formation and consumption of the high-entropy oxide layer on the surface during friction, which plays a role in solid lubrication and slowing down material loss.

Claims

1. A high-temperature resistant, oxidation-resistant, and wear-resistant multi-component carbide coating, characterized in that, The coating comprises: a CrY / CrYTiAl composite transition layer and a (TiCrNbAlY)C functional layer located on the composite transition layer; In the (TiCrNbAlY)C functional layer, the atomic percentage of C is 40%~60%, and the atomic percentages of the five metal elements Ti, Cr, Nb, Al and Y are all 5%~12%.

2. The high-temperature antioxidant and wear-resistant multi-component carbide coating according to claim 1, characterized in that: The thickness of the CrY / CrYTiAl composite transition layer is 50~500 nm; the thickness of the (TiCrNbAlY)C functional layer is 1~5 μm.

3. A method for preparing a high-temperature antioxidant and wear-resistant multi-component carbide coating as described in any one of claims 1 or 2, characterized in that, Includes the following steps: (1) A multi-arc ion plating system is used to deposit a CrY / CrYTiAl composite transition layer on the surface of a substrate that has been cleaned with Ar ions; The sputtering gas source is the inert gas Ar; The target materials used include one or more of Cr, Y, CrY, TiAl, and Ti; The target opening sequence is as follows: Cr, Y, CrY, TiAl, Ti, with a target opening time interval of 0~8 min; The chamber pressure is 0.4~0.8 Pa; The current of each cathode arc target is independently controlled to be 50~100 A; The substrate has a negative bias voltage of -100 to -400 V; The chamber temperature is 150~350 ℃; (2) Continue to deposit a (TiCrNbAlY)C functional layer on the composite transition layer; The sputtering gas source includes the reactive gas C2H2 and the inert gas Ar, with a flow rate ratio of C2H2 to Ar of (0.5~2):1; The chamber pressure is 0.3~0.9 Pa; The target materials used include one or more of Cr, Y, CrY, TiAl, Ti, and Nb; The current of each cathode arc target is independently controlled to be 50~130 A; The substrate has a negative bias voltage of -100 to -400 V; The chamber temperature is 150~350 ℃.

4. The method according to claim 3, characterized in that, The substrate is a metallic material, including 304 stainless steel, 9Cr18 stainless steel, Inconel 718 alloy, TC4 alloy, aluminum, copper and their alloys.

5. The method according to claim 3, characterized in that, The negative bias voltage of the substrate described in steps (1) and (2) is kept consistent or controlled independently.

6. The application of a high-temperature antioxidant and wear-resistant multi-component carbide coating as described in any one of claims 1 or 2 in the surface protection of high-temperature components in the aerospace, nuclear industry, or metallurgical fields.

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