The Ni/Ge0.9Sn0.1 solid-state reaction was monitored by combining in situ X-ray diffraction, in-plane reciprocal space map measurements and in-plane pole figures. A sequential growth was shown, in which the first phase formed was an Ni-rich phase. Then, at 518 K, the mono-stanogermanide phase Ni(Ge0.9Sn0.1) was observed. This phase was stable up to 873 K. Special attention has been given to the nature and the crystallographic orientation of the Ni-rich phase obtained at low temperature. It is demonstrated, with in-plane pole figure measurements and simulation, that it was the ∊-Ni5(Ge0.9Sn0.1)3 metastable phase with a hexagonal structure.
Metastable phase in binary and ternary 12-carat gold alloys at low temperature