X-ray photoelectron spectroscopy study of the metal/cermet interface

Interfacial reactions between aluminium and polycrystalline cermet TiC0.6 w ere investigated using x-ray photoelectron spectroscopy, Auger electron spe ctroscopy and x-ray diffraction. It was found that titanium exists in two c hemical states. The carbide and oxide of titanium can be detected simultane ously, and the atomic ratio of Ti:C:O is 5:3:2. This suggests that TiC0.6 i s a Ti-oxycarbide or oxygenated TiC composite: Ti5C3O2 (TiO2 + 4TiC(0.75)) When Al is deposited in vacuum on the Ti-oxycarbide surface, the active Al atoms react chemically only with TiO2 at room temperature, but not with Tic (0.75) in Ti-oxycarbide. The reaction products are Al2O3 and the intermetal lic compound Al-3 Ti. Annealing the Al/TiC0.6 interface at 750 degrees C, A l reacts also with TiC0.75 to form a brittle Al4C3 phase.