INTERFACIAL REACTIONS BETWEEN TITANIUM FILM AND SINGLE-CRYSTAL ALPHA-AL2O3

Titanium is commonly used to join metals and ceramics by active metal brazing methods. In this work, titanium was sputter deposited on to single-crystal alpha-Al2O3 substrates and the interfacial reactions between the titanium film and the Al2O3 substrate were studied. Al2O3 was reduced by titanium when samples were annealed at 973 and 1173 K for 300 s in an argon gas flow. Metallic aluminium was produced at the interface, and this diffused from the interface into the titanium film. At 1173 K, the intermetallic compound Ti3Al and the intermediate titanium oxides, such as Ti2O and TiO, were formed. The Al(O) diffusion is important in stimulating interfacial reactions.