Reaction of evaporated Ti films with large-grained Al substrates

We have studied the reaction kinetics of titanium films on large-grained aluminium substrates during furnace annealing in vacuum for temperatures between 450–550°C. Oxygen was profiled by elastic resonance¹⁶O(, )¹⁶O backscattering. A TiAl₃ aluminide layer always forms at the Ti/Al interface. In addition, a second TiAl₃ layer grows at the free Ti surface when the contamination of the annealing ambient by oxygen-carrying species is reduced during annealing. Otherwise, the nucleation of the second compound layer is inhibited by an oxygen-rich surface layer of the Ti.