双A层MAX相Mo2Ga2C的热压烧结研究

本工作采用真空热压烧结的方法, 研究Mo₂Ga₂C粉体的烧结性能, 制备致密的Mo₂Ga₂C块体材料, 并且表征所制备材料的微观结构。实验发现750 ℃是合适的烧结温度, 过高的烧结温度(850 ℃)会导致样品分解, 主要产物为Mo₂C。在750 ℃烧结过程中, 随着烧结时间的延长, 样品的晶粒没有明显长大, 但是样品内部空隙显著变小, 内部织构增强, 相对密度明显提高。因为Mo₂Ga₂C晶体的片状结构, 热压烧结过程中, 部分片状晶粒会偏转, 导致烧结样品的多数晶粒的(00l)晶面会倾向垂直于热压方向。在750 ℃烧结8 h, 可以得到几乎完全致密(相对密度98.8%)的Mo₂Ga₂C块体材料。

Hot-pressing Sintering of Double-A-layer MAX Phase Mo2Ga2C

Mo₂Ga₂C, a double-A-layer MAX, is reported to be films or powders. This paper researched the sintering properties of M₂Ga₂C powders to make dense bulk samples by vacuum hot pressing. It was found that 750 ℃ was a suitable sintering temperature, while higher temperature (850 ℃) resulted in decomposition of Mo₂Ga₂C yielding to main product of Mo₂C. During sintering process at 750 ℃, its grain size did not increase obviously with sintering time, meanwhile the size of pores decreased markedly and the relative density increased significantly with the increasing sintering time. Additionally, the hot-pressed samples had obvious texture. Due to layering, some grains changed their orientations during sintering, of which most of the (00l) planes in the hot-pressed samples preferred to be perpendicular to the direction of hot press. Almost fully densed Mo₂Ga₂C bulk (relative density: 98.8%) was obtained by hot pressing at 750 ℃ for 8 h. This advantage of the method suggested that it can serve as a promising preparation for Mo₂Ga₂C, a double-A-Layer MAX.