Interfacial reactions of thin titanium aluminide films with Al2O3 films and with sapphire

✍ Scribed by M. Nathan; C.R. Anderson; J.S. Ahearn

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 718 KB
• Volume: 162
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/0921-5093(90)90034-z

✦ Synopsis

Interracial reactions between thin (approximately 500 A) titanium aluminide films with 30, 50 and 70 at.% aluminum, and both electron-beam evaporated A1203 and sapphire, were investigated with transmission electron microscopy (TEM) and X-ray photoemission spectroscopy (XPS) at 700-900 °C. Single-phase aluminides are formed by reacting thin multilayered Ti/A1 stacks at temperatures below 700 °C. All three aluminides react with alumina at 900 °C after 100 s. The reaction involves in-diffusion of oxygen into, and out-diffusion of aluminum from the aluminide, resulting in titanium enrichment of the aluminide and the formation of titanium oxides. The reaction is spatially limited. The observed reactivity of aluminum-rich aluminides with AI203 contrasts with all previously reported bulk results, and indicates that on a nanometer scale, titanium aluminides are chemically incompatible with AI203.