A novel ternary nitride whisker: MgSiN2 whisker and its growth mechanism

Abstract

The MgSiN₂ whisker, as a novel ternary nitride, exhibits considerable potential as an advanced high-temperature toughening material. In this study, the supported catalysis method was employed to synthesize the MgSiN₂ whisker for the first time, as well as for the impacts of catalyst precursor and heat treatment temperature on the phase, morphology, and growth mechanism of the MgSiN₂ whisker were investigated. The results showed that the precursor of Fe, Co, and Ni catalyst precursors all had catalytic effects on the growth of the MgSiN₂ whisker. The Co catalyst precursor exhibited superior catalytic efficacy, significantly enhancing the yield and length-to-diameter ratio of the MgSiN₂ whisker. Furthermore, as the heat treatment temperature increases, the growth mechanism of the MgSiN₂ whisker transitions from vapor–solid (VS) to vapor–liquid–solid (VLS), and ultimately to a dislocation-mediated growth mechanism. The successful synthesis of the MgSiN₂ whisker, measuring approximately 0.6 µm in diameter and 20–30 µm in length, was achieved at 1400°C. Simultaneously, the Co catalyst precursor had been observed to effectively enhance the adsorption of gaseous Mg and N₂ on the Si₃N₄(1 1 0) surface, facilitating the growth of the MgSiN₂ whisker.