Metallurgical model of in situ synthesised TiB_2/Fe composite coatings during PTA process

摘要

The in situ synthesised TiB_2/Fe composite coatings were deposited by plasma transferred arc powder surfacing process. The distribution of TiB? in the TiB_2/Fe composite coatings was investigated in this paper. It is found that there is more TiB_2 distributed on the top than at the bottom of the coatings in general. In addition, it is also found that heat input plays an important role in the distribution of TiB_2 in the coatings. A small quantity of TiB_2 whiskers are obtained in the coating with high energy density. While sufficient TiB_2 is produced with appropriate energy density, TiB_2 lumps will be obtained with small total energy input, and the concentration gradient of TiB_2 will appear with a large total energy input. Finally, the metallurgical model of in situ synthesised TiB_2/Fe composite coatings by plasma transferred arc process is extracted.