Tin whisker growth from titanium-tin intermetallic and the mechanism

Spontaneous growth of metal whiskers, represented by tin whiskers, has haunted tin-based platings and solder joints for decades and caused huge losses to the electronics industry. Despite numerous efforts, the underlying growth mechanism has been resisting interpretation, and the whiskering phenomenon even continues to expand its territory. Here, we report the growth of tin whiskers from a Ti6Sn5 intermetallic. These tin whiskers share similar characteristics with those found on the platings or solder joints, but grow more and faster, with finer diameters. After tin whisker growth, Ti6Sn5 retains its crystal structure, implying a dealloying process. Combining experimental and first-principles calculation results, we analyzed the growth mechanism of tin whiskers in detail, and proposed a diffusion-based growth model. The strain energy stored in Ti6Sn5 during deformation provides a driving force for whisker growth, and the short-circuit diffusion paths generated by such deformation accelerate whisker growth. These findings identify the critical role of intermetallic substrate in the whiskering phenomenon, shedding new light for comprehensively understanding the whisker growth mechanisms. Furthermore, the plenty and rapid growth of tin whiskers also means a new method for the preparation of one-dimensional metallic materials. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

This research investigates the growth of tin whiskers from a Ti6Sn5 intermetallic and finds that they share similar characteristics with whiskers found on platings or solder joints, but they grow more and faster with finer diameters. The study analyzes the growth mechanism using experimental and computational methods, proposing a diffusion-based growth model. It reveals the critical role of the intermetallic substrate in the whiskering phenomenon and provides new insights for comprehensive understanding of whisker growth mechanisms. Additionally, the abundant and rapid growth of tin whiskers also offers a new method for preparing one-dimensional metallic materials.