Korean Institute of Surface Engineering

pISSN : 1225-8024 | eISSN : 3399-8403


한국표면공학회지 (32권2호 100-108)

Microstructure and Corrosion Characteristics of Al-Si Diffusion Coated Ni Base Super alloy

Al-Si확산코팅에 따른 Ni기 초합금의 미세조직과 부식특성


국방과학연구소;충남대학교 금속공학과;한려대학교 제철금속학과;


The microstructure and corrosion properties of Al-Si diffusion coated PWA1426 alloy have been investigated. Experimental variables are included temperatures of heat-treatment and coating thickness. The microstructure of coated layer and corrosion properties were analysed by SEM, EDS and hot corrosion test. Two major processes have been found to contribute to microstructural changes in the coating. These are, firstly, the transformation of the NiAl to other $Ni_2Al_3$-based phase and secondly, the precipitation of Cr containing phases. Specimens heat treated at $1080^{circ}C$ showed superior corrosion resistance to heat treated at $880^{circ}C$. These increase in life was attributed to the transformation of NiAl and increased coating thickness of PWA1426 alloy.