Phase equilibria in the Pt-In-P system

X-ray diffraction and electron probe microanalysis were used to determine the phase equilibria in the In-Pt-P system at 725 and 600 °C. The observed binary phases were consistent with the assessed phase diagrams from the literature. Three ternary phases were found. The major difference between the 725 and 600 °C isotherms was the phases in equilibrium with InP. At 600 °C, the binary phases Pt3In7 and PtP2 were in equilibrium with InP. However, a tie-line transition from InP-Pt3In7 to In-PtP2 was found between 600 and 725 °C. The binary phases which were found to be stable in thin film form on InP were consistent with the phase equilibria data. From the tie-line change, the enthalpy of formation of PtP2 at 298 K was estimated to be −350±40 kJ/mol.