Interface structure and distribution characteristics of vacuum fusion sintered Ni-based alloy coating containing rare earth element

The microstructure, phase structure, and distributing characteristics of alloy elements and microhardness of vertical section of vacuum fusion sintered Ni-based alloy coatings were studied in this paper. The results showed that rare earth elements (Ce+La) improved structure of Ni60 coating, needle-shaped phase transformed to small globular-shaped phase, and the metallurgical binding of interface between the steel matrix and coating was reinforced. New second phases WC, Ni₂B, NiB and Cr_6.5Ni_2.5Si precipitated in Ni60+RE coating. Rare earth elements held back the diffusion of Ni, Cr and Si atoms from coating to steel matrix and Fe atom from steel matrix to coating, and alleviated dilution function of Fe atom from steel matrix to Ni-based alloy coating. Rare earth elements increased Ni, Cr, and Si contents, and decreased Fe content in the coating too. The microhardness of Ni-based coating could apparently be enhanced by introduction of rare earth elements, and microhardness values of two kinds of coating reached their maximum values at 0.4 mm near by coating surface.