Mechanism of formation of intermetallic coatings by the Cold Spray Technology

Abstract

Abstract In the present paper, results of a study of a TinAlm intermetallic coating obtained on the surface of titanium (Ti) by the method of Cold Gas Spraying (CGS) and heating to a temperature above the melting point of aluminum (Al) are reported. It is shown that the structure of the resultant coating depends on the heating temperature. At temperature T = 930K the coating consists of a TiAl3 intermetallic layer. At temperature T = 1270K a layered coating is formed. In this coating, a TiAl3 intermetallic layer, adjacent to the Ti surface, is followed by a second intermetallic layer consisting of Ti3Al and Ti2Al sublayers. The microhardness of the Ti3Al/Ti2Al double-layer coating proves to be three times higher than that of Ti. A qualitative explanation to the mechanism of formation of the layered coating is proposed.