Mechanism and mitigation of spontaneous Ga whisker growth on Cr2GaC


Spontaneous growth of A-element whiskers on Mn+1AXn (MAX for short) phase materials poses a barrier to their practical applications, since it casts doubts on their stability. In this study, Ga whisker growth on sintered Cr2GaC samples was investigated. The elemental source for spontaneous growth of Ga whiskers is identified as the free Ga contained in the Cr2GaC material, not the lattice atoms from Cr2GaC grains, which removes the doubts on the stability of Cr2GaC material. The growth behavior and morphologies of the Ga whiskers follow a new catalysis-based model, with cleavage planes of Cr2GaC grains involved as nucleation sites. This model explains and predicts well the growth behavior of the whiskers. The mitigation strategy based on this model is in principle simple: to prevent free Ga in Cr2GaC material or limit it to a certain level; to avoid cleavage plane of Cr2GaC grains; to achieve high density of the Cr2GaC material.

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Corresponding authors

Correspondence to WuBian Tian or ZhengMing Sun.

Additional information

This work was supported by the National Natural Science Foundation of China (Grant Nos. 51501038 & 51731004), and the Fundamental Research Funds for the Central Universities (Grant No. 2242018K40109).

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Zhang, P., Ding, J., Liu, Y. et al. Mechanism and mitigation of spontaneous Ga whisker growth on Cr2GaC. Sci. China Technol. Sci. 63, 440–445 (2020).

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  • MAX phase
  • whisker growth
  • nucleation model
  • mitigation strategy