Thermal stability and selective nitridation of Cr2AlC in nitrogen at elevated temperatures

作者:Xing, Guangchao; Wan, Hang; Deng, Chengji; Di, Jinghui; Ding, Jun; Ma, Beiyue; Wang, Zhoufu; Zhu, Hongxi; Yu, Chao*
来源:Ceramics International, 2022, 48(22): 33151-33159.
DOI:10.1016/j.ceramint.2022.07.252

摘要

The thermal stability and selective nitridation of Cr2AlC under a high-temperature nitrogen atmosphere were studied. Cr2AlC began to decompose beyond 1073 K in N-2, and the activation energy was estimated to be 108.93 kJ.mol(-1). Initially, the selective nitridation led to the generation of an AlN layer, which shielded the underlying Cr2AlC and the process was dominated by a surface reaction. The final products were AlN, Cr7C3 and Cr3C2, and the weaker Cr-Al bonds in Cr2AlC facilitated the rapid diffusion of aluminum from the interior outwards. As the reaction proceeded, micropores were observed on the grain surface, as well as a loose structure, which facilitated the diffusion of N-2 and thus accelerated the reaction. Finally, the intensive reaction involving Cr2AlC and N-2 could be attributed to the gas diffusion channels caused by improved temperature and continuous escape of vaporized aluminum.

  • 单位
    东北大学