Abstract
The structure and constituents in two types of nickel-base self fluxing alloy coatings thermal sprayed and subsequently fused were precisely investigated by use of X-ray diffraction analysis, electron probe microanalysis, scanning electron microscopy and transmission electron microscopy. JIS-MSFNi1 alloy coating was composed of primary nickel solid solution and Ni3B phase between primary nickel grains with a small amount of Ni-Ni3B eutectic. In case of JIS-MSFNi4 alloy coating, lumpy crystals and two kinds of rod-like crystals appeared in addition to Ni-Ni3B eutectic. It was found that the lumpy crystal is M6C carbide containing chromium, molybdenum and nickel. The rod-like crystals are M3B2 boride of tetragonal structure and M7C3 carbide of hexagonal structure. Metal constitution of M3B2 are chromium and molybdenum and M7C3 contains mainly chromium. The nickel phase in the Ni-Ni3B eutectic of MSFNi4 alloy coating has the superlattice structure.
