CN-119352016-B - Implementation method of integrated ultra-high temperature environment barrier composite coating

Abstract

A method for realizing integrated ultra-high-temperature environment barrier composite coating includes such steps as pre-coating high-entropy alloy or its boride layer and Mo metal pre-coating, pre-oxidizing to deposit Si-B, forming Mo-Si-B multi-layer structure, cold spraying the composite paint of metal silicide and silicon dioxide, high-temp sintering to form three-dimensional net-shaped composite self-healing layer, and cold spraying or magnetically sputtering alloy oxide to form water-resistant steam layer. The invention complements the advantages of different components through the integrated coating preparation process, and can realize the effective protection of various refractory alloys in a wide temperature range (room temperature-1700 ℃).

Inventors

• SU RANRAN
• ZHANG HONGLIANG

Assignees

• 上海交通大学
• 复旦大学

Dates

Publication Date

20260512

Application Date

20241022

Claims (4)

1. 1. A preparation method of an ultra-high temperature environmental barrier integrated composite coating is characterized by comprising the steps of pre-coating a high-entropy alloy layer on the surface of a substrate, pre-coating a layer of pure molybdenum metal pre-coating, performing vacuum high-temperature sintering, performing silicon-boron co-embedding deposition, forming an ordered Mo-Si-B multilayer structure in the molybdenum metal layer through a pre-oxidation process, preparing a composite self-healing layer and a water vapor resistant layer on the surface of the Mo-Si-B multilayer structure through cold spraying, and forming a three-dimensional net structure in the composite self-healing layer after high-temperature sintering; The pure molybdenum metal precoat is prepared by spraying a slurry on a substrate by mixing 99.9% pure, 1-5 μm Mo powder and 2.0% by weight 1000-4000% in ethanol Is obtained by using hydroxypropyl cellulose as a binding agent; the composite self-healing layer and the waterproof vapor layer are prepared by the following steps: a) Preparing refractory alloy silicide and SiO 2 powder slurry, mixing the two powders and cellulose in alcohol according to a certain proportion, and fully stirring and mixing to form uniform slurry; b) Uniformly spraying the slurry on the surface of the sample by using a compressed air spray gun; c) Preparing refractory alloy oxide powder slurry, uniformly mixing oxide powder and cellulose according to a proportion, and dissolving the mixture in alcohol to form slurry; d) Uniformly spraying refractory alloy oxide slurry on the surface of a sample; e) Placing the sample in air, heating to 1500-1600 ℃ and sintering for 2 hours to form a composite self-healing layer and a water vapor resistant layer; The ultra-high temperature environment barrier integrated composite coating is specifically a reinforced diffusion barrier layer, a Mo-Si-B-diffusion barrier layer, a composite self-healing layer and a water vapor resistant layer which are sequentially arranged on a substrate and are composed of high-entropy alloy; the high-entropy alloy is W-Mo-Ta-Nb-V; The refractory alloy silicide is MoSi 2 ; The refractory alloy oxide is HfO 2 .
2. 2. The method for preparing the ultra-high temperature environmental barrier integrated composite coating according to claim 1, wherein the vacuum high temperature sintering is carried out for 2 hours at a temperature rise/fall rate of 15 ℃ per minute up to 1750 ℃.
3. 3. The method for preparing the ultra-high temperature environmental barrier integrated composite coating according to claim 1, wherein the silicon-boron co-embedding deposition is carried out by mixing and grinding Si, B and activator powder for 30 minutes to obtain a uniform mixture, adding Al 2 O 3 filler, embedding a Mo precoat sample into a sealed alumina crucible, and then placing into a sealed alumina tube filled with argon gas in a furnace for deposition treatment; The mass ratio of Si to B is 35:1.
4. 4. An ultra-high temperature environmental barrier integrated composite coating, characterized in that it is prepared according to the method of any one of claims 1-3.

Description

Implementation method of integrated ultra-high temperature environment barrier composite coating Technical Field The invention relates to a technology in the field of new material coatings, in particular to a realization method of an integrated ultra-high temperature environment barrier composite coating. Background A key factor in the operation of the new multi-component refractory alloy (RMPEA or RHEA) in an oxidizing environment is the formation of a protective oxide layer. However, in high temperature oxidation environments, most refractory alloys have difficulty forming a dense oxide layer or forming an oxide layer often has difficulty providing protection due to an excessively high oxygen diffusion rate. Under thermal cycling and thermal loading, severe cracks generated in the stress-promoted coating will cause the coating to fail and fail. Protective coatings compatible with the substrate can be implemented to provide protection to the substrate with little impact on the overall performance of the substrate. Under the working condition of rapid cooling and rapid heating cycle, the existing high-temperature ablation resistant coating has the defects that the coating structure is easy to crack, peel and the like due to the difference of the thermal expansion coefficients between the coating and the substrate, and the coating cannot cope with the working environment of complex gas components, for example, high-temperature vapor H 2 O in the working gas reacts with SiO 2 components in the coating, so that SiO 2 is rapidly consumed, and the service life of the coating is reduced. Disclosure of Invention Aiming at the defects in the prior art, the invention provides a realization method of an integrated ultra-high temperature environment barrier composite coating, and the advantages of different components are complemented through an integrated coating preparation process, so that effective protection of various refractory alloys in a wide temperature range can be realized. The invention is realized by the following technical scheme: The invention relates to an implementation method of an integrated ultra-high temperature environment barrier composite coating, which comprises the steps of pre-coating a high-entropy alloy or boride layer thereof on the surface of a substrate, pre-coating a layer of pure molybdenum metal pre-coating, carrying out vacuum high-temperature sintering, carrying out silicon-boron co-embedding deposition, forming an ordered Mo-Si-B multilayer structure in the molybdenum metal layer through a pre-oxidation process, carrying out cold spraying on a composite coating formed by metal silicide and silicon dioxide on the surface of the Mo-Si-B multilayer, forming a composite self-healing layer of a three-dimensional network structure after air high-temperature sintering, carrying out cold spraying or magnetron sputtering on alloy oxide outside the composite self-healing layer to form a water vapor resistant layer, and carrying out sintering treatment. The high-entropy alloy or boride thereof refers to W-Mo-Ta-Nb, W-Mo-Ta-Nb-Zr, W-Mo-Ta-Nb-Hf, W-Mo-Ta-Nb-V or boride (W-Mo-Ta-Nb) B, (W-Mo-Ta-Nb-Zr) B, (W-Mo-Ta-Nb-Hf) B or (W-Mo-Ta-Nb-V) B. The metal silicide and the silicon dioxide refer to MoSi 2、WSi2 and SiO 2. The alloy oxide is HfO 2、ZrO2, mgO or CrTaO 4. The invention relates to an ultra-high temperature environment barrier integrated composite coating prepared by the method, which comprises a reinforced diffusion barrier layer, a Mo-Si-B oxidation-resistant diffusion barrier layer, a composite self-healing layer and a water vapor resistant layer, wherein the reinforced diffusion barrier layer, the Mo-Si-B oxidation-resistant diffusion barrier layer, the composite self-healing layer and the water vapor resistant layer are sequentially arranged on a substrate. Technical effects The invention utilizes an integrated composite coating design method, adds a diffusion-resistant refractory high-entropy alloy or boride thereof, a self-healing layer with an adjustable three-dimensional reticular structure and a high-temperature steam resistant layer on the basis of the original Mo-Si-B coating by a spraying process, a hot sintering process, an embedding codeposition process, a pre-oxidation treatment and the like, and realizes the integration of multiple functions of the coating compared with the prior art, thereby greatly improving the integrity, high-temperature oxidation resistance and complex environment durability of the coating. Drawings FIG. 1 is a flow chart of the present invention; FIG. 2 is a schematic view of the coating structure of the present invention; FIG. 3 is a schematic representation of the cross-sectional back-scattered electron images and elemental distribution of silicon and molybdenum after 10 hours of exposure to 1300℃air for a Mo pre-coat and Mo-Si-B coating sample prepared in a two-step process in the example; FIG. 4 (a) is a graph showing mass change curves of uncoa