Disilicide solid solutions, phase diagram, and resistivities. I. TiSi ₂-WSi₂

The pseudobinary system TiSi2-WSi2 has been investigated from about 85% TiSi2 to 100% WSi2 up to a temperature of 1100 °C. The equilibrium phase diagram which has been established contains a continuous (from 15% to 100% WSi2) solid solution with a hexagonal structure (TaSi2 type) at low temperatures, below ∼550 °C. At about 550 °C WSi2-rich alloys split into two phases, the normal tetragonal phase of WSi2, which has a very limited solubility for TiSi2, and the hexagonal (TaSi 2) phase with the amount of WSi2 in solution decreasing with increasing temperature at about 50% at 1100 °C. The resistivity of the different alloys has been studied as a function of annealing temperature. There is considerable excess resistivity due to alloy scattering and no evidence of a marked difference in resistivity between the two phases.