High-resolution EPMA X-ray images of mother liquid inclusions in a Pd sub(2)Ga single crystal

During crystal growth from solution inclusions of different compositions were trapped at the rim of a Pd sub(2)Ga single crystal. Their fine-grained (< 5 mu m) internal structure demands special requirements for electron microprobe analysis, realized by low-voltage (5 keV) element mapping applying a step size of 0.138 mu m for each pixel. It can be shown, that these inclusions represent an isolated chemical system, and that crystallisation upon cooling follows the expected thermodynamic phase relations. Thus the final composition in the centre of the inclusion consists of a small-scale mixture of PdGa and Pd sub(5)Ga sub(3) evolved out of a solid-solid decomposition of Pd sub(5)Ga4.