J. Cho, Hanyang Univ., Seoul, South Korea; Y. Ji, C. Lee, Hanyang University, Seoul, South Korea; S. Y. Hwang, RIST, Pohang, South Korea
The blended coatings have a non-uniform microstructure due to the differences of physical and thermophysical properties of the blend components leading deterioration of the mechanical and tribological properties of the coatings. In order to improve mechanical and tribological properties, nanostructured composite feedstock was prepared by heat treatment after spray drying including a nano component (under 100nm Cr2O3). The blended and nanostructured composite powder feedstocks containing 60 wt% NiCr, 20 wt% Cr2O3, 10 wt% Ag, 10 wt% BaF2/CaF2 were deposited by atmospheric plasma spraying (APS). The wear behavior was characterized using a rig test at ambient temperature and at 350¡É. The nanostructured composite coating had more uniform, finer microstructure resulting in excellent mechanical properties (Vickers microhardness and bonding strength). Spray dried composite coating showed lower friction coefficient and excellent wear resistance than the blended coating.
