Thermal conductivity of Ni3X and Pt3X in ordered and disordered states

Thermal conductivities are measured for a series of Ni3X and Pt3X compounds in which an ordered L12 and f.c.c. disordered structures are formed when the constituent X belongs to the first long period in the periodic table. An empirical rule is found for both ordered and disordered structures that the thermal conductivity tends to decrease as the distance of the constituent X increases in the horizontal direction from the location of Ni and Pt in the periodic table. This trend is quite isomorphic with that of dilute solid solutions of Ni-X or Pt-X, although the magnitude is different. For most Ni3X and Pt3X compounds, thermal conductivity increases with increasing temperature. The temperature coefficient of thermal conductivity is higher in the disordered compounds than in the ordered compounds.