A study of the Al-rich part of the Al–Ni–Pt alloy system

The Al–Ni–Pt phase diagram was studied in the compositional region from 50 to 100 at.% Al. Isothermal sections were determined at 1000, 900 and 790 °C. At 1000 °C the Al2Pt phase was found to extend up to ∼Al53Ni23Pt24 composition, separating the (Al3Pt2) and (Al3Ni2) phase fields. Two ternary structures were revealed. The one forming between ∼Al75Ni3Pt22 and Al75Ni9Pt16 is rhombohedral isostructural to Al28Ir9 and the other forming between ∼Al73Ni8Pt19 and Al72.5Ni18Pt9.5 has an orthorhombic ɛ6 structure typical of Al–Pd and Al–Rh.

► The Al-rich part of the Al–Ni–Pt alloy system was investigated for the first time at 790–1000 °C.
► The partial isothermal sections at 790, 900 and 1000 °C were constructed.
► Two ternary phases were found: a rhombohedral phase isostructural to Al28Ir9 and an orthorhombic ɛ6 structure typical of Al–Pd and Al–Rh.