Metallurgical model of in situ synthesised TiB 2 /Fe composite coatings during PTA process

The in situ synthesised TiB₂/Fe composite coatings were deposited by plasma transferred arc powder surfacing process. The distribution of TiB₂ in the TiB₂/Fe composite coatings was investigated in this paper. It is found that there is more TiB₂ 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 TiB₂ in the coatings. A small quantity of TiB₂ whiskers are obtained in the coating with high energy density. While sufficient TiB₂ is produced with appropriate energy density, TiB₂ lumps will be obtained with small total energy input, and the concentration gradient of TiB₂ will appear with a large total energy input. Finally, the metallurgical model of in situ synthesised TiB₂/Fe composite coatings by plasma transferred arc process is extracted.