CN108070859A - Refractory metal surfaces lamellar composite Ir/W high-temperature oxidation resistant coatings and preparation method thereof - Google Patents

Abstract

The invention discloses a layered composite Ir/W high-temperature anti-oxidation coating on the surface of a refractory metal, which comprises a metal W layer and a metal Ir layer in sequence, the thickness of the metal W layer is 3 μm to 15 μm; the thickness of the metal Ir layer is The thickness is 5 μm to 40 μm. The invention discloses a method for preparing the layered composite Ir/W high-temperature anti-oxidation coating. The method includes: 1. grinding, sandblasting, degreasing and pickling the surface of the refractory metal substrate; 2. performing pretreatment preparing a metal W layer on the surface of the final refractory metal substrate; 3. preparing a metal Ir layer on the surface of the metal W layer to obtain a layered composite Ir/W high-temperature oxidation-resistant coating. The invention introduces a metal W layer between the metal iridium coating and the refractory metal substrate as a bonding layer and a diffusion barrier layer, which solves the problem of insufficient bonding force between the Ir coating and the refractory metal substrate and the relationship between the Ir coating and the refractory metal under high temperature. The high-temperature interfacial diffusion reaction of the metal substrate shortens the life of the coating.

Description

Layered composite Ir/W high temperature anti-oxidation coating on refractory metal surface and preparation method thereof

technical field

The invention belongs to the technical field of high-temperature protection, and in particular relates to a layered composite Ir/W high-temperature anti-oxidation coating on a refractory metal surface and a preparation method thereof.

Background technique

Refractory alloys have excellent high-temperature strength and toughness and good processing properties, and have been widely used in the aerospace industry, aviation industry and atomic energy industry. However, refractory alloys are prone to severe oxidation and failure when used in ultra-high temperature oxidation environments. Therefore, improving the high temperature oxidation resistance of refractory metals is the key to ensuring their high temperature service performance. The most commonly used high-temperature protective coating for refractory metals is silicide coating. However, with the development of the aerospace industry, the service temperature of the hot end parts of refractory metals used in the new generation of high-specific impulse, orbital rocket engines and hypersonic vehicles It can reach more than 1700°C, and it has to withstand the erosion of high-temperature and high-speed gas. The traditional silicide coating has been difficult to meet the service requirements.

Metal iridium (Ir) itself has a melting point as high as 2440°C, and it has good chemical inertness, low oxygen permeability, and strong oxygen barrier ability at high temperatures. Iridium does not produce condensed oxides at temperatures above 1200°C, and the oxygen permeability at 2200°C is only 10 ^-14 g/(cm ² ·s). This makes its high-temperature anti-oxidation temperature up to 2100°C, which can meet the service requirements of refractory metals in harsh oxidizing environments.

The Ir coating cannot "self-heal" at high temperatures, and the coating must be complete in order to play a protective role. The maximum service temperature and effective life of the metal Ir coating are mainly determined by the loss of volatile oxides and the high-temperature interdiffusion between the coating and the substrate. Deposit HfO ₂ , ZrO ₂ , Y ₂ O ₃ and Al ₂ O ₃ oxide ceramic corrosion resistant layers on the surface of Ir coating, or prepare Ir-Ta, Ir-Hf, Ir-Ta-Al, Ir- Modified Ir coatings such as Pt and Ir-Al can reduce the impact of volatile oxide loss on the high temperature protection performance of the coating.

However, the high-temperature diffusion reaction between the metal Ir layer and the refractory metal at high temperature not only shortens the high-temperature service life of the metal Ir layer, but also deteriorates the high-temperature protection performance of the coating. Moreover, the interfacial diffusion reaction will also change the refractory metal substrate. The chemical composition and microstructure of the material surface affect the mechanical properties of the matrix. In addition, due to the high melting point of Ir and the refractory metal substrate, the coating often has insufficient interdiffusion between the coating and the refractory metal substrate during the preparation process, resulting in weak bonding between the coating and the substrate, which in turn makes the coating Cracking and peeling are prone to occur during the preparation process and under the alternating service environment of cold and hot.

Contents of the invention

The technical problem to be solved by the present invention is to provide a layered composite Ir/W high-temperature anti-oxidation coating on the surface of refractory metal for the above-mentioned deficiencies in the prior art. The introduction of a metal W layer as a bonding layer and a diffusion barrier layer significantly improves the interface bonding strength between the Ir coating and the refractory metal substrate, improves the thermal shock resistance of the coating, and the coating and substrate under high temperature conditions The degree of interdiffusion between them is significantly reduced, and the life of the coating is significantly improved. Therefore, to a certain extent, the coating solves the problem of insufficient bonding between the metal Ir layer and the refractory metal substrate and the high-temperature interfacial diffusion reaction between the metal iridium coating and the refractory metal substrate at high temperature, which shortens the life of the coating.

The technical scheme adopted in the present invention is: a layered composite Ir/W high temperature anti-oxidation coating on the surface of refractory metal, characterized in that the layered composite Ir/W high temperature anti-oxidation coating includes sequentially prepared on the refractory alloy substrate The metal W layer and the metal Ir layer on the surface, the metal W layer has the dual functions of a bonding layer and a diffusion barrier layer, and its thickness is 3 μm to 15 μm; the thickness of the metal Ir layer is 5 μm to 40 μm.

The above-mentioned layered composite Ir/W high-temperature anti-oxidation coating on the surface of refractory metal is characterized in that the thickness of the metal W layer is 9 μm to 11 μm, and the thickness of the metal Ir layer is 11 μm to 30 μm.

The above-mentioned layered composite Ir/W high-temperature anti-oxidation coating on the surface of refractory metal is characterized in that the thickness of the metal W layer is 10 μm, and the thickness of the metal Ir layer is 20 μm.

In addition, the present invention also provides a method for preparing the layered composite Ir/W high-temperature oxidation-resistant coating on the surface of refractory metal, characterized in that the method comprises the following steps:

Step 1. Carrying out grinding, sand blasting, degreasing treatment and pickling treatment on the surface of the refractory metal substrate in sequence to obtain the pretreated refractory metal substrate;

Step 2, preparing a metal W layer on the surface of the pretreated refractory metal substrate obtained in step 1 by magnetron sputtering or arc ion plating;

Step 3, using one or more of physical vapor deposition, chemical vapor deposition, thermal spraying, cold spraying and electrodeposition to prepare metal on the surface of the metal W layer on the refractory metal substrate in step 2 Ir layer, and finally a layered composite Ir/W high-temperature anti-oxidation coating is obtained on the refractory metal substrate.

The above-mentioned method is characterized in that the refractory metal described in step one is Nb alloy, Mo alloy or Ta alloy; the sand grains used in the sandblasting treatment are corundum sand, glass beads or zirconia sand, and the sandblasting The treatment pressure is 0.2MPa-0.8MPa, and the blasting time is 2min-8min.

The above-mentioned method is characterized in that the acid solution used in the pickling process described in step 2 is formed by mixing hydrofluoric acid and concentrated nitric acid by volume ratio (6～7):(3～4), and the hydrofluoric acid The mass concentration of the acid is 40%-60%, the mass concentration of the concentrated nitric acid is 65%-68%, and the pickling time is 1min-5min.

The above method is characterized in that before preparing the metal W layer in step 2, the surface of the pretreated refractory metal is cleaned by sputtering.

The above-mentioned method is characterized in that, the preparation method of the metal Ir layer described in step 3 adopts one of the existing vacuum physical vapor deposition, chemical vapor deposition, thermal spraying, cold spraying or electrodeposition coating preparation methods or a combination thereof Prepare the metal Ir layer so that its thickness reaches the requirement; the vacuum physical vapor deposition method includes but not limited to magnetron sputtering, electron beam physical vapor deposition, or arc ion plating; the chemical vapor deposition method includes but not limited to hot wire Chemical vapor deposition, plasma-assisted chemical vapor deposition or metal organic oxide chemical vapor deposition; the thermal spraying method includes arc spraying, supersonic flame spraying, atmospheric plasma spraying vacuum plasma spraying; the electrodeposition method includes but not limited to nano Powder composite electroplating or pulse electroplating; the combination of the above methods includes: alternately using two or more methods of vacuum physical vapor deposition, chemical vapor deposition, thermal spraying, cold spraying, and electrodeposition methods, and sequentially prepare the required thickness. Anti-high temperature oxidation protective outer layer; or two or more methods of the same kind using vacuum physical vapor deposition and chemical vapor deposition methods.

Compared with the prior art, the present invention has the following advantages:

1. The introduction of the metal W layer in the layered composite Ir/W high-temperature oxidation-resistant coating of the present invention can significantly improve the bonding force between the oxidation-resistant metal Ir layer and the refractory metal substrate. By optimizing the preparation process parameters of the metal W layer, By controlling its microstructure and surface state, a high-quality anti-oxidation metal Ir layer can be prepared on a refractory metal substrate with a metal W layer, and the coating does not peel and crack; at the same time, the prepared by this method The layered composite Ir/W metal coating has good thermal shock resistance and thermal shock resistance, and can provide high temperature protection for refractory metal substrates under cold and hot cycle conditions.

2. The introduction of the metal W layer in the layered composite Ir/W high-temperature anti-oxidation coating of the present invention can significantly reduce the degree of interdiffusion between the metal Ir layer and the refractory metal substrate under high temperature conditions. Compared with the single-layer metal Ir layer , the influence of interdiffusion between the coating and the substrate on the high temperature protection performance and service life of the coating and the mechanical properties of the refractory metal substrate is significantly reduced.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a photograph of the surface morphology of the metal W layer prepared in Step 2 of Example 1 of the present invention.

FIG. 2 is a photo of the cross-sectional microstructure of the metal W layer prepared in Step 2 of Example 1 of the present invention.

Fig. 3 is an EDS line scan analysis result of the metal W layer prepared in step 2 of Example 1 of the present invention.

Fig. 4 is a photograph of the surface morphology of the layered composite Ir/W high-temperature oxidation-resistant coating prepared in Example 1 of the present invention.

Fig. 5 is a cross-sectional microstructure photograph of the layered composite Ir/W high-temperature anti-oxidation coating prepared in Example 1 of the present invention.

Fig. 6 is the EDS line scan analysis result of the layered composite Ir/W high temperature anti-oxidation coating prepared in Example 1 of the present invention.

Fig. 7 is the XRD diffraction pattern of the layered composite Ir/W high-temperature anti-oxidation coating prepared in Example 1 of the present invention.

Fig. 8 is a cross-sectional SEM photo of the layered composite Ir/W high-temperature oxidation-resistant coating prepared in Example 2 of the present invention.

Fig. 9 is the analysis result of the EDS point at the position P1 in Fig. 8 .

Fig. 10 is the analysis result of the EDS point at the position P2 in Fig. 8 .

Detailed ways

Example 1

In this example, a layered composite Ir/W high-temperature anti-oxidation coating is prepared on the metal surface of Mo1, including a metal W layer and a metal Ir layer coated on the surface of the refractory alloy substrate in sequence, and the metal W layer has both a bonding layer and a diffusion layer. The double role of the barrier layer, its thickness is 11 μm; the thickness of the metal Ir layer is 11 μm.

The preparation method of the layered composite Ir/W high-temperature oxidation-resistant coating of this embodiment comprises the following steps:

Step 1. Carry out grinding treatment, sandblasting treatment, degreasing treatment and pickling treatment on the Mo1 metal substrate in sequence; the sand grains used in the sandblasting treatment are corundum sand; the pressure of the sandblasting treatment is 0.2MPa, and the sandblasting time is 2min; preferably, the refractory metal is immersed in acetone for degreasing treatment; the acid solution used in the pickling treatment is formed by mixing hydrofluoric acid and concentrated nitric acid in a volume ratio of 7:3, and the mass concentration of the hydrofluoric acid 50%, the mass concentration of the concentrated nitric acid is 67%, the time of pickling is 5min, the surface of the Mo1 metal substrate is silvery white and in the state of "pockmarked surface"; the Mo1 metal substrate is pre-oxidized before pickling.

Step 2. Prepare a metal W layer on the surface of the pretreated refractory metal substrate in step 1 by magnetron sputtering. Before preparing the metal W layer, sputter and clean the Mo1 metal substrate to remove surface pollutants and oxygen adsorption layers. , followed by metal W layer preparation, detailed process parameters are shown in Table 1;

Step 3, using a magnetron sputtering preparation method to prepare a metal Ir layer on the surface of the refractory metal with a metal W layer, and finally obtain a layered composite Ir/W high-temperature oxidation-resistant coating on the Mo1 metal substrate.

Table 1 Process parameters of layered composite Ir/W high-temperature anti-oxidation coating prepared by magnetron sputtering

It can be seen from FIG. 2 that the layered Ir/W coating prepared on the Mo1 metal surface in this embodiment is very continuous, and the metal Ir layer and the metal W layer are well combined. It can be seen from Figure 3 that the metal Ir layer grows preferentially along the (111) crystal plane. After 400 times of cyclic oxidation at 1400°C, the layered Ir/W coating prepared on the Mo1 metal surface in this example did not peel off significantly, showing good cyclic oxidation performance, and the interdiffusion between the coating and the substrate was not obvious.

Fig. 1 is a photo of the surface topography of the metal W layer prepared in the present embodiment, Fig. 2 is a photo of the cross-sectional microstructure of the metal W layer prepared in the present embodiment, and Fig. 3 is an EDS line of the metal W layer prepared in the embodiment of the present invention Scanning analysis results, as can be seen from Fig. 1, Fig. 2 and Fig. 3, the metal W layer prepared on the Mo1 metal surface in this embodiment has no voids at the interface with the substrate, the coating is continuous, the thickness is uniform, and the surface microscopic appearance is rough. It is beneficial to enhance the bonding force between the metal Ir layer and the metal W layer.

Fig. 4 is the photo of the surface topography of the layered composite Ir/W high-temperature oxidation-resistant coating prepared in the present embodiment, and Fig. 5 is the cross-sectional microstructure photo of the layered composite Ir/W high-temperature oxidation-resistant coating prepared in the present embodiment , Fig. 6 is the EDS line scanning analysis result of the layered composite Ir/W high temperature anti-oxidation coating prepared in this embodiment, as can be seen from Fig. 4, Fig. 5 and Fig. 6, the present embodiment is prepared on the Mo1 metal surface The layered Ir/W coating is very continuous, and the metal iridium layer is well combined with the metal tungsten layer.

Fig. 7 is the XRD diffraction pattern of the layered composite Ir/W high temperature anti-oxidation coating prepared in this example. It can be seen from the figure that the metal Ir layer grows preferentially along the (111) crystal plane. After 400 times of cyclic oxidation at 1400°C, the layered Ir/W coating prepared on the Mo1 metal surface in this example did not peel off significantly, showing good cyclic oxidation performance, and the interdiffusion between the coating and the substrate was not obvious.

Example 2

This embodiment includes the following steps:

In this embodiment, a layered composite Ir/W high-temperature anti-oxidation coating is prepared on the surface of Nb521 niobium alloy, including a metal W layer and a metal Ir layer coated on the surface of the refractory alloy substrate in sequence, and the metal W layer has both a bonding layer and a metal Ir layer. The dual role of the diffusion barrier layer has a thickness of 3 μm; the metal Ir layer has a thickness of 5 μm.

The preparation method of the layered composite Ir/W high-temperature oxidation-resistant coating of this embodiment comprises the following steps:

Step 1. Carry out grinding treatment, sand blasting treatment, degreasing treatment and pickling treatment on the Nb521 niobium alloy substrate in sequence; the sand particles used in the sand blasting treatment are corundum sand; the pressure of the sand blasting treatment is 0.4MPa, and the sandblasting time is For 3min; preferably, the refractory metal is immersed in acetone for degreasing treatment; the acid solution used in the pickling treatment is formed by mixing hydrofluoric acid and concentrated nitric acid in a volume ratio of 7:3, and the mass of the hydrofluoric acid The concentration is 50%, the mass concentration of the concentrated nitric acid is 67%, the pickling time is 2min, and the surface of the Nb521 niobium alloy substrate is in a silvery white and "pockmarked" state.

Step 2. Prepare a metal W layer on the surface of the pretreated Nb521 niobium alloy substrate in step 1 by magnetron sputtering. Before preparing the metal W layer, sputter and clean the Nb521 niobium alloy substrate to remove surface pollutants and oxygen adsorption. layer, followed by the preparation of the metal W layer, the thickness of the metal W layer is 3 μm, and the detailed process parameters are shown in Table 2;

Step 3: Using the magnetron sputtering preparation method, a metal Ir layer with a thickness of 5 μm is prepared on the surface of the refractory metal with a metal W layer, and finally a layered composite Ir/W high-temperature oxidation-resistant coating is obtained on the Nb521 niobium alloy substrate.

Table 2 Process parameters for preparing layered composite Ir/W high-temperature anti-oxidation coatings by magnetron sputtering

Fig. 8 is the cross-sectional SEM photo of the layered composite Ir/W high temperature oxidation resistant coating prepared in this example, Fig. 9 is the EDS point analysis result at the P1 position in Fig. 8, and Fig. 10 is at the P2 position in Fig. 8 As can be seen from Fig. 8, Fig. 9 and Fig. 10, the Ir/W layered composite coating prepared on the surface of Nb521 niobium alloy in this embodiment, between Nb521 substrate/metal W layer/metal Ir layer The bonding between them is good and the coating is continuous. After 200 times of cyclic oxidation at 1500°C, the layered Ir/W coating prepared on the surface of Nb521 niobium alloy in this example did not peel off obviously, showing good cyclic oxidation performance, and the interdiffusion between the coating and the substrate was not obvious .

Example 3

In this embodiment, a layered composite Ir/W high-temperature oxidation-resistant coating is prepared on the surface of the Ta10W tantalum alloy, including a metal W layer and a metal Ir layer coated on the surface of the refractory alloy substrate in sequence, and the metal W layer has both a bonding layer and a metal Ir layer. The dual role of the diffusion barrier layer is 10 μm thick; the metal Ir layer is 20 μm thick.

The preparation method of the layered composite Ir/W high-temperature oxidation-resistant coating of this embodiment comprises the following steps:

Step 1. Carry out grinding treatment, sandblasting treatment, degreasing treatment and pickling treatment on the Ta10W tantalum alloy substrate in sequence; the sand particles used in the sandblasting treatment are corundum sand; the pressure of the sandblasting treatment is 0.8MPa, and the sandblasting time is It is 8min; Preferably, the refractory metal is immersed in acetone for degreasing treatment; the acid solution used in the pickling treatment is formed by mixing hydrofluoric acid and concentrated nitric acid in a volume ratio of 7:3, and the mass of the hydrofluoric acid The concentration is 50%, the mass concentration of the concentrated nitric acid is 67%, and the pickling time is 5 minutes. The surface of the Ta10W tantalum alloy metal substrate is silvery white and "pockmarked".

Step 2. Prepare a metal W layer on the surface of the refractory metal substrate pretreated in step 1 by magnetron sputtering. Before preparing the metal W layer, sputter and clean the Ta10W tantalum alloy substrate to remove surface pollutants and oxygen adsorption. layer, followed by the preparation of the metal W layer, the thickness of the metal W layer is 10 μm, and the detailed process parameters are shown in Table 1;

Step 3, using the magnetron sputtering preparation method to prepare a 20 μm metal Ir layer on the surface of the refractory metal with a metal W layer, and finally obtain a layered composite Ir/W high-temperature oxidation-resistant coating on the Mo1 metal substrate.

Table 3 Process parameters of layered composite Ir/W high-temperature anti-oxidation coating prepared by magnetron sputtering

In the layered composite Ir/W coating prepared on the surface of the Ta10W tantalum alloy in this example, the bonding between the substrate/metal W layer/metal Ir layer is good, and the coating is continuous. After 400 times of cyclic oxidation at 1800°C, the layered composite Ir/W coating prepared on the surface of Ta10W tantalum alloy in this example did not peel off obviously, showing good cyclic oxidation performance, and the interdiffusion between the coating and the substrate was not obvious.

Example 4

In this embodiment, a layered composite Ir/W high-temperature anti-oxidation coating is prepared on the surface of the Ta12W tantalum alloy, including a metal W layer and a metal Ir layer coated on the surface of the refractory alloy substrate in sequence, and the metal W layer has both a bonding layer and a metal Ir layer. The dual role of the diffusion barrier layer is 15 μm thick; the metal Ir layer is 40 μm thick.

The preparation method of the layered composite Ir/W high-temperature oxidation-resistant coating of this embodiment comprises the following steps:

Step 1. Carry out grinding treatment, sandblasting treatment, degreasing treatment and pickling treatment on the Ta12W tantalum alloy substrate in sequence; the sand particles used in the sandblasting treatment are corundum sand; the pressure of the sandblasting treatment is 0.8MPa, and the sandblasting time is It is 8min; Preferably, the refractory metal is immersed in acetone for degreasing treatment; the acid solution used in the pickling treatment is formed by mixing hydrofluoric acid and concentrated nitric acid in a volume ratio of 7:3, and the mass of the hydrofluoric acid The concentration is 50%, the mass concentration of the concentrated nitric acid is 67%, and the pickling time is 5 minutes. The surface of the Ta12W tantalum alloy metal substrate is silvery white and "pockmarked".

Step 2. Prepare a metal W layer on the surface of the pretreated refractory metal substrate in step 1 by arc ion plating. Before preparing the metal W layer, sputter and clean the Ta12W tantalum alloy substrate to remove surface pollutants and oxygen adsorption layers. , followed by the preparation of the metal W layer, the thickness of the metal W layer is 15 μm, and the detailed process parameters are shown in Table 1;

Step 3: Prepare a metal Ir layer with a thickness of 40 μm on the surface of the refractory metal with a metal W layer by using an arc ion plating preparation method, and finally obtain a layered composite Ir/W high-temperature oxidation-resistant coating on the Ta12W tantalum alloy substrate.

In the layered composite Ir/W coating prepared on the surface of the Ta12W tantalum alloy in this example, the bonding between the substrate/metal W layer/metal Ir layer is good, and the coating is continuous. After 300 times of cyclic oxidation at 1800°C, the layered composite Ir/W coating prepared on the surface of the Ta12W tantalum alloy in this example did not peel off obviously, showing good cyclic oxidation performance, and the interdiffusion between the coating and the substrate was not obvious.

Example 5

In this embodiment, a layered composite Ir/W high-temperature anti-oxidation coating is prepared on the surface of the Ta12W tantalum alloy, including a metal W layer and a metal Ir layer coated on the surface of the refractory alloy substrate in sequence, and the metal W layer has both a bonding layer and a metal Ir layer. The dual role of the diffusion barrier layer has a thickness of 9 μm; the metal Ir layer has a thickness of 30 μm.

The preparation method of the layered composite Ir/W high-temperature oxidation-resistant coating of this embodiment comprises the following steps:

Step 1. Carry out grinding treatment, sandblasting treatment, degreasing treatment and pickling treatment on the Ta12W tantalum alloy substrate in sequence; the sand particles used in the sandblasting treatment are corundum sand; the pressure of the sandblasting treatment is 0.6MPa, and the sandblasting time is It is 8min; Preferably, the refractory metal is immersed in acetone for degreasing treatment; the acid solution used in the pickling treatment is formed by mixing hydrofluoric acid and concentrated nitric acid in a volume ratio of 7:3, and the mass of the hydrofluoric acid The concentration is 50%, the mass concentration of the concentrated nitric acid is 67%, and the pickling time is 4 minutes. The surface of the Ta12W tantalum alloy metal substrate is in a silvery white and "pockmarked" state.

Step 2. Prepare a metal W layer on the surface of the pretreated refractory metal substrate in step 1 by arc ion plating. Before preparing the metal W layer, sputter and clean the Ta12W tantalum alloy substrate to remove surface pollutants and oxygen adsorption layers. , followed by the preparation of the metal W layer, the thickness of the metal W layer is 15 μm, and the detailed process parameters are shown in Table 1;

Step 3: Prepare a metal Ir layer with a thickness of 30 μm on the surface of the refractory metal with a metal W layer by using an arc ion plating preparation method, and finally obtain a layered composite Ir/W high-temperature oxidation-resistant coating on the Ta12W tantalum alloy substrate.

In the layered composite Ir/W coating prepared on the surface of the Ta12W tantalum alloy in this example, the bonding between the substrate/metal W layer/metal Ir layer is good, and the coating is continuous. After 300 times of cyclic oxidation at 1800°C, the layered composite Ir/W coating prepared on the surface of the Ta12W tantalum alloy in this example did not peel off obviously, showing good cyclic oxidation performance, and the interdiffusion between the coating and the substrate was not obvious.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any way. All simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present invention still belong to the technical aspects of the present invention. within the scope of protection of the scheme.

Claims (7)

1. a layered composite Ir/W high-temperature oxidation-resistant coating on the surface of a refractory metal, characterized in that, the layered composite Ir/W high-temperature oxidation-resistant coating comprises successively prepared metal W layers on the surface of the refractory alloy substrate and The metal Ir layer, the metal W layer has a thickness of 3 μm to 15 μm; the metal Ir layer has a thickness of 5 μm to 40 μm. 2. according to a kind of refractory metal surface layered composite Ir/W high temperature anti-oxidation coating according to claim 1, it is characterized in that, the thickness of described metal W layer is 9 μ m～11 μ m, the thickness of described metal Ir layer 11 μm to 30 μm. 3. according to a kind of refractory metal surface layered composite Ir/W high temperature anti-oxidation coating according to claim 2, it is characterized in that, the thickness of described metal W layer is 10 μ m, the thickness of described metal Ir layer is 20 μ m . 4. a method for preparing the refractory metal surface layered composite Ir/W high temperature oxidation resistant coating as claimed in claim 1, 2 or 3, is characterized in that, the method may further comprise the steps: Step 1. Carrying out grinding, sand blasting, degreasing treatment and pickling treatment on the surface of the refractory metal substrate in sequence to obtain the pretreated refractory metal substrate; Step 2, preparing a metal W layer on the surface of the pretreated refractory metal substrate obtained in step 1 by magnetron sputtering or arc ion plating; Step 3, using one or more of physical vapor deposition, chemical vapor deposition, thermal spraying, cold spraying and electrodeposition to prepare metal on the surface of the metal W layer on the refractory metal substrate in step 2 Ir layer, and finally a layered composite Ir/W high-temperature anti-oxidation coating is obtained on the refractory metal substrate. 5. according to the described method of claim 4, it is characterized in that, the refractory metal described in step 1 is Nb alloy, Mo alloy or Ta alloy; Zircon sand, the pressure of the blasting treatment is 0.2MPa-0.8MPa, and the blasting time is 2min-8min. 6. according to the described method of claim 4, it is characterized in that, the acid solution that the pickling process described in the step 2 adopts is mixed by hydrofluoric acid and concentrated nitric acid by volume (6～7):(3～4) As a result, the mass concentration of the hydrofluoric acid is 40%-60%, the mass concentration of the concentrated nitric acid is 65%-68%, and the pickling time is 1min-5min. 7. The method according to claim 4, characterized in that, before preparing the metal W layer in step 2, the surface of the pretreated refractory metal is cleaned by sputtering.