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CN-121992403-A - Niobium alloy surface antioxidation composite coating, preparation method and application thereof

CN121992403ACN 121992403 ACN121992403 ACN 121992403ACN-121992403-A

Abstract

The invention discloses an antioxidant composite coating on the surface of a niobium alloy, and a preparation method and application thereof, belonging to the technical field of coatings and preparation methods thereof. The antioxidation composite coating comprises a Cr-Si transition layer, wherein a compact Al-B-Y 2 O 3 modified MoSi 2 antioxidation layer and a YSZ heat insulation layer are sequentially arranged on the surface of the Cr-Si transition layer. The preparation method comprises the following steps of preprocessing the surface of a substrate, preparing a Cr-Si transition layer on the surface of the substrate, preparing an Al-B-Y 2 O 3 modified MoSi 2 oxidation resistant layer on the surface of the Cr-Si transition layer, and spraying a YSZ heat insulation layer on the surface of the Al-B-Y 2 O 3 modified MoSi 2 oxidation resistant layer. The invention provides a gradient composite coating with high interface bonding strength, effective barrier element interdiffusion and excellent oxidation resistance and heat insulation performance and a preparation method thereof.

Inventors

  • LIU YUTONG
  • ZHAN MENGLING
  • LI ZHENGXIAN
  • YANG KAI

Assignees

  • 江苏集萃表面工程技术研究所有限公司

Dates

Publication Date
20260508
Application Date
20260227

Claims (10)

  1. 1. The anti-oxidation composite coating on the surface of the niobium alloy is characterized by sequentially comprising a Cr-Si transition layer, an Al-B-Y 2 O 3 modified MoSi 2 anti-oxidation layer and a YSZ heat insulation layer from inside to outside, wherein in the Cr-Si transition layer, si element is gradually increased along the direction of the YSZ heat insulation layer to the modified MoSi 2 anti-oxidation layer.
  2. 2. The niobium alloy surface oxidation-resistant composite coating as claimed in claim 1, wherein the thickness of the Cr-Si transition layer is 15-29 μm, the thickness of the Al-B-Y 2 O 3 modified MoSi 2 oxidation-resistant layer is 50-70 μm, and the thickness of the YSZ heat-insulating layer is 100-130 μm.
  3. 3. The niobium alloy surface oxidation-resistant composite coating according to claim 1, wherein in the Cr-Si transition layer, the mass percentage of Nb is 75-80 wt%, the mass percentage of Cr is 10-15 wt%, and the balance is Si.
  4. 4. The niobium alloy surface oxidation-resistant composite coating according to claim 1, wherein in the Al-B-Y 2 O 3 modified MoSi 2 oxidation-resistant layer, the mass fraction of Al is 3-8wt%, the mass fraction of B is 1-3wt%, the mass fraction of Y 2 O 3 is 0.5-2wt%, and the balance is MoSi 2 ; In MoSi 2 , the mass percentage of Si is 25-30wt%, the mass percentage of O is less than 1wt%, and the balance is Mo.
  5. 5. The niobium alloy surface oxidation-resistant composite coating as claimed in claim 1, wherein the coating is well combined with the substrate, the combination strength is 60-66Mpa, the coating maintains a complete structure after 60s ablation at 2000 ℃, and the linear ablation rate is 0.027-0.037mm/s.
  6. 6. The application of the niobium alloy surface oxidation resistant composite coating in the high-temperature aerobic environment with the temperature of more than 800 ℃ according to any one of claims 1 to 5, wherein the high-temperature aerobic environment with the temperature of more than 800 ℃ comprises a high thrust-weight ratio engine and a high-temperature structural material for aerospace.
  7. 7. The method for preparing the niobium alloy surface oxidation-resistant composite coating according to any one of claims 1 to 5, which is characterized by comprising the following steps: firstly, pretreating the surface of a niobium alloy matrix; Preparing a Cr-Si transition layer on the surface of the substrate by using a double-glow plasma surface metal infiltration method, wherein the process of the double-glow plasma surface metal infiltration method comprises the steps of introducing argon with the vacuum degree of 0.1-0.2Pa, keeping the argon at 35-40Pa, keeping the cathode voltage of a workpiece at 500-600V, keeping the source voltage at 1000-1100V, keeping the temperature at 900-1000 ℃ and keeping the temperature for 2-3h; Step three, preparing composite powder with a core-shell structure; The core is Al powder and B 4 C powder, the Al powder and B 4 C powder are subjected to high-energy ball milling according to the mass ratio of 3:1 to form (Al-B 4 C) composite particles with the size of 5-15 mu m, Uniformly wrapping a layer of Y 2 O 3 sol precursor on the surface of (Al-B 4 C) composite particles by a sol-gel method, forming a layer of nanocrystalline Y 2 O 3 shell after heat treatment, The outermost shell layer is prepared by depositing a compact MoSi 2 layer on the surface of the particles wrapped with the Y 2 O 3 shell layer by adopting chemical vapor deposition; Step four, spraying the composite powder with the core-shell structure by using a plasma spraying method, preparing an Al-B-Y 2 O 3 modified MoSi 2 oxidation resistant layer on the surface of the Cr-Si transition layer, wherein the plasma spraying powder is the composite powder with the core-shell structure, the plasma gas is Ar, the power is 25-35kW, the spraying distance is 100-120mm, the powder feeding speed is 25-35g/min, and the moving speed of a spray gun is 500-700mm/s; And fifthly, spraying a YSZ heat insulation layer on the surface of the Al-B-Y 2 O 3 modified MoSi 2 oxidation resistant layer by using a plasma spraying method, wherein the plasma spraying powder is agglomerated and sintered 8YSZ powder, the plasma gas is Ar, the power is 35-45kW, the spraying distance is 120-150mm, the powder feeding rate is 30-40g/min, and the moving speed of a spray gun is 800-1000mm/s.
  8. 8. The preparation method of the high-energy ball milling process according to claim 7, wherein in the third step, the high-energy ball milling process comprises the steps of ball-to-material ratio of 10:1, ball milling rotation speed of 250-300rpm and ball milling time of 5 hours; The sol-gel method comprises the steps of taking 1.5-3.0 wt% of the mass of a Y 2 O 3 shell layer by the mass of (Al-B 4 C) composite particles, taking yttrium nitrate hexahydrate as a precursor, taking a mixed solvent of absolute ethyl alcohol and deionized water with the volume ratio of 4:1 as a solvent, treating 50-100 g (Al-B 4 C) composite particles each time, wherein the liquid-solid ratio is 5:1-10:1, the ball-material ratio is 10:1, the ball-milling rotating speed is 250-300rpm, the ball-milling time is 5 hours, carrying out rotary evaporation guided deposition at 40-50 ℃ for 1.5-3 hours, and then carrying out vacuum drying at least at 60 ℃ for 2-3 hours; The heat treatment process comprises heating to 600-650 deg.C at 1-3 deg.C/min, maintaining in argon for 1-3 hr, and cooling with furnace.
  9. 9. The method of preparing the polymer film according to claim 7, wherein in step three, the chemical vapor deposition process comprises placing the particles coated with the Y 2 O 3 shell layer in a CVD reactor, introducing a mixed gas of MoCl 5 、SiHCl 3 and H 2 at 850-950 ℃, wherein the volume ratio of MoCl 5 ：SiHCl 3 ：H 2 is 1 (3.0-3.5) (30-50), the pressure is 5-15 kPa, and the deposition time is 60-120 minutes, so that a dense MoSi 2 layer is uniformly deposited on the surfaces of the particles.
  10. 10. The preparation method of the agglomerated and sintered 8YSZ powder, as set forth in claim 7, characterized in that in the fifth step, the preparation method comprises the steps of ball-milling and mixing nanoscale YSZ powder, deionized water, ammonium polyacrylate with the addition amount of 0.5-1.0 wt% of the mass of the YSZ powder and polyvinyl alcohol aqueous solution with the addition amount of 2-4 wt% of the mass of the YSZ powder to prepare slurry with the solid content of 35-45 wt%, wherein the mass concentration of the polyvinyl alcohol aqueous solution is 5-8 wt%, spraying and granulating to obtain hollow spherical agglomerates, sintering in air, wherein the sintering temperature is 1200-1300 ℃, preserving for 1-2 hours, naturally cooling in a furnace, sieving the sintered powder, and selecting powder with the particle size of 45-100 μm.

Description

Niobium alloy surface antioxidation composite coating, preparation method and application thereof Technical Field The invention relates to an antioxidant composite coating on the surface of a niobium alloy and a preparation method and application thereof, in particular to a coating for improving the antioxidant performance of the surface of the niobium alloy and a preparation method and application thereof, belonging to the technical field of coatings and preparation methods thereof. Background The niobium alloy is a high-temperature structural material with great application prospect in the aerospace field because of high melting point, good high-temperature strength and processability. However, niobium alloys can undergo catastrophic "nitrogen embrittlement" and severe oxidation in high temperature (especially above 800 ℃) aerobic environments, severely limiting their use in practical service environments. To solve this problem, it is often necessary to apply a protective coating to the niobium alloy surface. Although the conventional coating system such as a silicide coating (such as NbSi 2) can provide a certain oxidation resistance, the thermal expansion coefficients of the coating and a niobium alloy matrix are different, and stress is easy to generate in the thermal cycle process, so that the coating is cracked and peeled off. And the coating element can interdiffuse with the matrix element at high temperature, which may lead to degradation of matrix properties or failure of coating protection properties. In addition, the traditional silicide coating mainly solves the problem of oxidization resistance, and the heat insulation capability is insufficient for the requirement of a new generation of high thrust-weight ratio engine on the heat barrier performance. Therefore, the development of the multi-layer composite coating which can be firmly combined with the niobium alloy matrix, effectively prevent high-temperature oxidation and has obvious heat insulation effect is important to promote the application of the niobium alloy in an ultra-high temperature environment. Disclosure of Invention The invention aims to overcome the defects of the prior art, and aims to provide the niobium alloy surface oxidation-resistant composite coating with long-acting oxidation resistance, good thermal shock resistance, good heat insulation effect and strong binding force. The invention further aims to provide a preparation method of the niobium alloy surface oxidation-resistant composite coating. The invention further aims at providing an application of the niobium alloy surface oxidation-resistant composite coating. Technical proposal The invention discloses an anti-oxidation composite coating on the surface of a niobium alloy, which comprises a Cr-Si transition layer, an Al-B-Y 2O3 modified MoSi 2 anti-oxidation layer and a YSZ heat insulation layer, wherein the surface of the Cr-Si transition layer is sequentially provided with the modified MoSi 2 anti-oxidation layer and the YSZ heat insulation layer, and Si element in the Cr-Si transition layer is gradually increased along the YSZ heat insulation layer towards the modified MoSi 2 anti-oxidation layer. Further, the thickness of the Cr-Si transition layer is 15-29 mu m, the thickness of the modified MoSi 2 antioxidation layer is 50-70 mu m, and the thickness of the YSZ heat insulation layer is 100-130 mu m. Further, in the Cr-Si transition layer, the mass percentage of Nb is 75-80 wt%, the mass percentage of Cr is 10-15 wt%, and the balance is Si. The main phase composition of the silicide diffusion layer formed by siliconizing the surface of the niobium alloy matrix is (Nb, X) Si 2 (wherein X is an alloy element in the niobium alloy (the niobium alloy is C-103 niobium alloy), such as Zr, hf, ti and the like). The layer forms metallurgical bonding with the matrix through interdiffusion, the components are in gradient change, the thermal expansion coefficient transition is gentle, the bonding force between the coating and the matrix is greatly improved, and the thermal stress is relieved. Further, al-B-Y 2O3 is sprayed on the Cr-Si transition layer to modify MoSi 2 oxidation-resistant layer, in the layer, silicon element can form a compact SiO 2 glass film at high temperature to provide main oxidation resistance, al can be oxidized preferentially to Si at high temperature to form an extremely stable alpha-Al 2O3 film, al 2O3 and SiO 2 can be mutually dissolved to form more compact aluminosilicate glass with lower oxygen diffusion rate, high-temperature oxidation resistance is greatly improved, an oxidation product B 2O3 of B is in a liquid state at 600-900 ℃, can flow extremely fast and heal microcracks of a coating in the temperature region, so that Pesting phenomenon is restrained, rare earth element Y serving as an active element can be enriched at an interface of SiO 2 and the coating, adhesiveness of the oxidation film is remarkably improved, and spalling of the