Spontaneous growth of Sn whiskers and a new formation mechanism

The mechanism for spontaneous tin (Sn) whisker growth has been elusive for nearly 70 years. This study is to understand this phenomenon based on a new substrate system rather than traditional ones (Sn and its alloys). On ball-milled Ti/Sn/C samples, spontaneous growth of Sn whiskers different from general ones was observed. Ti2SnC grains were found to form during ball milling process, and the Sn atom planes of such Ti2SnC grains served as nucleation sites for Sn whiskers formation. The findings and the new mechanism proposed herein might renovate the research of spontaneous growth of metal whiskers, and are of significance to uncovering the phenomenon which resisted interpretation.