Evaluation of the effects of the crystallinity of kinetically sprayed Ni–Ti–Zr–Si–Sn bulk metallic glass on the scratch response

A bulk amorphous Ni–Ti–Zr–Si–Sn powder produced using an inert gas atomization was sprayed by a kinetic spraying process that is basically a solid-state deposition process onto a mild steel substrate and they were successfully overlaid onto the mild steel substrate. In order to evaluate the tribological behavior of the sprayed Ni–Ti–Zr–Si–Sn bulk metallic glass coatings, a partially crystallized coating and a fully crystallized coating were prepared by isothermal heat treatments. Tribological properties were investigated—friction coefficient, hardness and amorphous phase fraction of coating layer. Surface morphologies and depth in the wear tracks were observed and measured by scanning electron microscopy and α-step. From the examination of the scratch wear track microstructure, transition from ductile-like deformation micro-cutting to brittle-deformation micro-fracturing in the scratch groove was observed with the increase of the crystallinity.