Spontaneous Ga whisker formation on FeGa3

FeGa₃ has attracted considerable attention as potential material for many fields, whereas the whiskering phenomenon may cast doubts on its applications. Spontaneous Ga whisker formation was observed on the ball-milled FeGa₃-Ga. The sample made from ball-milled FeGa₃ powders free of elemental Ga are immune to the Ga whisker formation, even if all the processing parameters were the same as the FeGa₃-Ga composite sample. In addition, several nano-sized Ga whiskers were found on the pressed FeGa₃-Ga composite without ball milling, and the as-synthesized FeGa₃-Ga grew only tiny Ga balls on the surface. These whiskering phenomena do not follow the traditional metal whisker formation mechanisms. A newly proposed catalysis-based mechanism, in which the cleavage planes of FeGa₃ grains act as heterogeneous nucleation sites and the elemental Ga provides Ga atoms for whisker formation, is employed to explain Ga whisker formation on FeGa₃.