A self-generated high-temperature diffusion barrier by in-situ reaction on the surface of refractory metal and its preparation method

Abstract

The invention discloses a refractory metal surface in-situ reaction self-generation high-temperature diffusion barrier. The refractory metal surface in-situ reaction self-generation high-temperature diffusion barrier is located between refractory metal and sintered silicide high-temperature protection coating coated on the surface of the refractory metal, and SiC serves as the main phase. The invention further discloses a preparing method of the refractory metal surface in-situ reaction self-generation high-temperature diffusion barrier. According to the method, graphene slurry or graphene oxide slurry and silicide composite suspension slurry are sequentially preset on the pre-treated refractory metal matrix surface, through sintering, the in-situ reaction self-generation high-temperaturediffusion barrier is obtained, the in-situ reaction self-generation high-temperature diffusion barrier reduces the high-temperature mutual diffusion rate between the high-temperature protection coating and the refractory metal matrix, the high-temperature oxidation resistance of the high-temperature protection coating is ensured, the high-temperature service life is prolonged, due to the in-situ reaction self-generation high-temperature diffusion barrier, the interfacial compatibility is improved, and the refractory metal-diffusion barrier-high-temperature protection coating has the good heatcycle resistance and thermal shock resistance.

Description

technical field [0001] The invention belongs to the technical field of high-temperature protection of refractory metals, and in particular relates to an in-situ reaction self-generated high-temperature diffusion barrier on the surface of refractory metals and a preparation method thereof. Background technique [0002] Refractory metals have excellent high-temperature strength and toughness and good processing properties, and have been widely used in aerospace and atomic energy industries. However, there are oxidation resistance problems in the application of refractory alloys in ultra-high temperature oxidizing environments. Applying ultra-high temperature protective coatings on the surface of refractory metals can significantly improve their high-temperature oxidation resistance and prolong the high-temperature service life of refractory metals. The most widely used high-temperature protective coatings on refractory metal surfaces are silicide coatings, aluminide coatings,...

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Problems solved by technology

[0003] However, there are significant differences in the chemical composition of the above-mentioned coatings and the refractory metal substrate, and the chemical activities of the components in the coating and the substrate are different, and interdiffusion between the coating and the substrate is inevitable during service.

On the one hand, interdiffusion leads to a large consumption of effective anti-high temperature oxidation components (Si, Al, Ir, etc.) in the coating, which greatly shortens the life of the coating. Moreover, matrix elements diffuse into the coating, causing changes in the chemical composition of the coating. , thereby reducing the high-temperature oxidation resistance of the coating; on the other hand, interfacial diffusion reactions can occur between the coating and some components in the matrix to form brittle intermetallic compound phases or topological close-packed phases, resulting in the formation of In the harmful phase area, the formation of these precipitates not only consumes the solid solution strengthening elements of the refractory metal matrix and weakens the solid solution strengthening effect of the solid solution elements, but also the precipitates are often the origin of cracks and the channels for cracks to rapidly expand, significantly Reduced creep rupture life of refractory metal substrates

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