Development of a new slurry coating design for the surface protection of gas turbine components

SURFACE & COATINGS TECHNOLOGY

卷:374

Article

Gregoire, Benjamin¹  Bonnet, Gilles¹  Pedraza, Fernando¹ 

[1] Univ La Rochelle, CNRS, Lab Sci Ingn Environm, LaSIE,UMR 7356, Ave Michel Crepeau, F-17042 La Rochelle 1, France

关键词: Superalloys;    Intermetallics;    Slurry coatings;    Aluminizing;    Diffusion;   

DOI  :  10.1016/j.surfcoat.2019.06.020

来源: Elsevier

【 摘 要 】

A new slurry coating design incorporating a first layer of Cr microparticles at the substrate surface and a surmounting second layer of Al microparticles to enrich the substrate with Al was investigated. The microstructure of the coating was tailored by adjusting the initial thicknesses of Cr and Al layers. The intermediate layer of Cr microparticles acted as a barrier to molten Al by forming Al-Cr intermetallic compounds thereby suppressing the highly exothermic reactions usually observed between molten Al and nickel-based materials. This also significantly decreased the inward diffusion rate of Al towards the substrate at 700 degrees C. Annealing at 1100 degrees C then promoted the outward diffusion of nickel atoms from the substrate and their combination with Al from the synthesized Al-Cr intermetallic phases compounds resulting in the direct formation of beta-NiAl with expelled Cr. The mechanisms of formation of the diffusion layers and the influence of Cr on the aluminizing progress are discussed.

【 授权许可】

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