Coating resistant to high temperature, high humidity and oxygen corrosion and preparation method thereof

Abstract

The invention discloses a coating resistant to high temperature, high humidity and oxygen corrosion and a preparation method thereof. The coating resistant to high temperature, high humidity and oxygen corrosion is arranged on the surface of a ceramic matrix composite substrate, and comprises a bonding layer and an RE2X2O7 surface layer, wherein the bonding layer is one of Si, SiO2 and SiC, the RE2X2O7 surface layer is of a pyrochlore type crystal structure, wherein RE is La or Sm, and X is Zr or Hf. The preparation method comprises the following steps: (1) preparing a bonding layer suspension; (2) preparing an RE2X2O7 suspension; (3) preparing a bonding layer preformed layer; (4) preparing an RE2X2O7 surface layer preformed layer; and (5) preparing the coating resistant to high temperature, high humidity and oxygen corrosion. The coating resistant to high temperature, high humidity and oxygen corrosion disclosed by the invention is good in thermal matching performance with the substrate, and capable of stably working for a long time in a strong-oxidizing / corrosive fuel gas erosion environment; the preparation method has the advantages of being simple in equipment, fast to form and the like; the prepared coating is high in bonding strength with the substrate.

Description

technical field [0001] The invention belongs to the field of preparation of coating materials, and relates to a coating resistant to high temperature and wet oxygen corrosion and a preparation method thereof, in particular to a rare earth zirconium / hafnate coating with a pyrochlore structure that can be applied to the field of ceramic matrix composite materials and its preparation method. Background technique [0002] At present, the service environment of advanced power systems such as aviation, aerospace engines, and gas turbine engines is a high-temperature, water-vapor-rich, and oxygen-rich environment. In this environment, ceramic matrix composites are an excellent candidate material with low density and high strength. , high toughness, high temperature resistance, good anti-oxidation and anti-ablation performance, etc., but its anti-high temperature wet oxygen corrosion performance is not satisfactory. Structural materials SiC / SiC composite materials, C / SiC composite m...

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Problems solved by technology

However, RE2X2O7 is also insufficient as the top layer material of the coating, for example, RE2 The X2O7 coating has a high coefficient of thermal expansion, and it is easy to cause thermal mismatch with the substrate with a low thermal expansion coefficient. Microcracks often occur during the preparation process, which affects the The reliability and protection performance of the material, so it is usually necessary to prepare a bonding layer with a thermal expansion coefficient similar to that of the substrate between the surface layer and the substrate. For example, the patent "CN 103434209 A" prepared a layer of NiCoCrAlY As the bonding layer, the double-layer composite coating with pyrochlore structure Pr2Zr2O7 as the surface layer has good High temperature resistance, low thermal conductivity and high thermal expansion coefficient, etc., but this coating system is only suitable for substrates with high thermal expansion coefficients such as superalloys, and the preparation process is plasma spraying and electron beam physical vapor deposition, the production efficiency is low and Not suitable for the preparation of large-sized and complex-structured workpieces

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