Rapid and massive growth of tin whisker on mechanochemically decomposed Ti2SnC

Abstract

Metallic whiskers grown on MAX phases bring concerns on their stability, and also draw intense attention because they share the similarity with the troublesome tin whiskers primarily found on Sn-based solders used in electronics. Herein, we report the rapid and massive growth of tin whiskers associated with Ti2SnC, a MAX phase, and it is found that the whisker growth propensity correlates with the decomposition degree of Ti2SnC. Tin atoms released from mechanochemically decomposed Ti2SnC have high chemical potential and spontaneous crystallization occurs. The similar phenomenon can also happen to several other MAX phases containing low melting point metal at A–site, and the composition of whiskers can be tuned by changing the composition of A–site layer of MAX phase, which bodes well a paradigm-shifting means for preparing metallic whiskers. In addition, the fundamental role of active tin atoms in whisker growth manifested here shall lay foundation for developing whisker-mitigating methods for MAX phases, and furthermore, help comprehensively understand the growth mechanism of the tin whiskers haunted electronic industry for many decades.