The Bureau of Mines has sought clarification of the ti-tin system by studying the phases formed by diffusion reactions between titanium and titanium nitride. Reaction couples were prepared by embedding pockets of tin powder in arc-melted buttons of titanium. Specimens were vacuum-annealed at nominal temperatures of 800 deg, 950 deg, 1,200 deg, and 1,500 deg c. Metallographically mounted cross sections from reacted specimens and from some that were not annealed were examined optically with an electron microprobe, with an electron microscope, and by x-ray diffraction. Each annealed specimen contained a segregated core primarily of o-phase material, an e-phase diffusion layer, an o-phase diffusion layer, and host metal. On the basis of corresponding microprobe analyses, and considering results of certain other research, a new phase diagram is proposed. It contains no qualitative innovations, but the quantitative adjustments are significant.
Ch. in Microstructural Sci., Vol. 2; American Elsevier Pub. Company, Inc., New York, PP. 101-114