The existence of Ni₃MSb phases in ternary nickel-M-antimony systems (where “M” represents aluminum, gallium, or indium)

Phases of the nominal composition Ni₃MSb (where “M” represents aluminum, gallium, or indium) were found to occur in their respective ternary systems. They were analyzed by x-ray diffraction and were found to exhibit the B8_1.5′ crystal structure, similar to that of Ni₃GaAs. These phases were shown by differential thermal analysis (DTA) to be stable between room temperature and their melting points, which were determined to be >1150 °C, 1066 °C, and 1091 °C for Ni₃AlSb, Ni₃GaSb, and Ni₃InSb, respectively. An analysis of their respective constituent binary systems suggested that these phases were not true ternary compounds, but rather represented specific compositions of extensive solid solutions of constituent binary phases. Speculations were made as to the solution behavior of these phases. The Ni₃MSb phases were predicted to form initially in nickel/MSb diffusion couples, in an analogy to what is observed in nickel/GaAs diffusion couples.