Abstract
Intermetallic Ti-Al-based coatings were synthesized by mechanical alloying in a vibratory ball mill and subsequent annealing. A titanium layer was deposited on aluminum specimens and an aluminum layer and aluminum-titanium mixture were deposited on titanium specimens. Under the effect of milling balls, powder particles deposit at the substrates, forming layers that have a very good cohesion with the substrate. During subsequent heating, diffusion layers on the basis of titanium-aluminum phases are synthesized as a result of the chemical interaction between titanium and aluminum. In the case of titanium layer deposited on aluminum, the temperature interval of transformations is 600–650°C; first, a Ti 3 Al 5 -based phase is formed; then, as diffusion saturation with Al increases, an Al 2 Ti-based layer appears; and finally, the Al 3 Ti compound is formed. The reaction rates depend on the temperature and the duration of annealing. On titanium with a (Ti + Al) layer deposited on its surface, the Al 3 Ti, Al 2 Ti, TiAl, and Ti 3 Al compounds are formed in a temperature interval of 600–900°C. In the case of deposition a homogeneous aluminum layer on titanium, only Al 3 Ti and Ti 3 Al phases were observed after annealing.