Atomized tin-induced bimetallic whisker growth

The spontaneous growth of metal whiskers has long posed reliability challenges in electronic devices, often resulting in short-circuit failures. Recent findings on the rapid and extensive formation of tin (Sn) whiskers on Ti₂SnC substrates underscore the critical role of atomized Sn in whisker growth. In this study, mechanochemically decomposed Ti₂SnC, capable of quantitatively and efficiently generating large amounts of atomized Sn, was implanted to Sn, Bi, and Pb metal matrices. After three days of being annealed at 60 °C, numerous whiskers grown on all implanted matrices, proving the critical role of atomized Sn in whisker growth. Notably, SnBi bimetallic and solid solution whiskers were detected. TEM analysis proved that the formation of SnBi whiskers was caused by the released latent heat of crystallizing atomized Sn, which creates SnBi micro-melt pools at the interface, facilitating interface flow and supplying the necessary constituents for SnBi bimetallic and solid solution whisker formation. Likewise, SnPb bimetallic whiskers were observed in Pb matrices implanted with the mechanochemical decomposed Ti₂SnC. These findings provide two contrasting strategies for future applications: effectively suppressing whisker formation and intentionally synthesizing bimetallic nanowires.