LAUSR

Spontaneous Sn whisker growth on Sn-containing substrates has resisted interpretation for several decades. In this paper, Ti2SnC-Sn and Ti2SnC samples were prepared and then cultivated in the same conditions. Many Sn whiskers had appeared on the ball milled Ti2SnC-Sn sample after being stored in air for 40 days, while no whisker grew on the Ti2SnC-Sn samples without ball milling although the cultivation time had been extended to more than half a year. Moreover, even though it was ball milled, the Sn-free Ti2SnC sample did not grow any whisker. The whiskers formed on this system share typical features with the ones grown on Sn platings and solders, while they do not follow any of the existing growth models. A catalysis-based whisker formation model, in which the cleavage planes of Ti2SnC grains act as heterogeneous nucleation sites, is proposed, which well interprets Sn whisker formation in the ball milled Ti2SnC-Sn system.