Effect of Ni concentrations on the microhardness of GaNiSb ternary alloys

The solid solution hardening of GaNiSb ternary alloys at different concentrations of Ni was investigated by means of Vickers indentation microhardness measurements at room temperature. All the bulk GaNiSb samples were grown by vertical Bridgman technique. The substitution of Ni for Ga changes the microhardness, which increases and attains a maximum in agreement with the theory. We have found that a limited range of solid solution of Ni in GaSb shows this behaviour. From X-ray diffraction (XRD) study, a linear lattice parameter-composition relation, as postulated by Vegard's law, is valid for different concentrations of Ni in GaNiSb ternary alloys.