Formation and properties of a Zr-based amorphous coating by laser cladding

(Zr_0.53Al_0.1Ni_0.05Cu_0.3Ti_0.02)₉₉Y₁ (at%) coating with amorphous layer of about 180 μm thick was prepared on a steel substrate by using laser cladding method. The coating is compact and shows good metallurgical bonding with substrate. The microstructure, microhardness and corrosion behavior along the depth from the coating surface to the substrate were investigated. It is found that a gradient structure consisted of amorphous surface layer, amorphous–crystalline transitional layer and substrate is formed after the laser cladding. The microhardness and corrosion behavior exhibit variation with the microstructural evolution at different depths from the coating surface. The microhardness and corrosion resistance in 3.5 wt% NaCl solution of the amorphous surface layer are comparable to those of the as-cast Zr-based BMG with the same composition, and higher than those of the steel substrate.