Microstructure and formation mechanism of in-situ TiC-TiB2/Fe composite coating

Steel matrix composite coatings locally reinforced with in situ TiC-TiB2 particulates were prepared by argon arc cladding(AAC) with different mass fractions of Fe and Ti+B4C powders as the binding materials. The microstructure, micro-hardness and wear resistance were investigated using SEM, XRD, Micro-hardness Tester, and Friction and Wear Tester, respectively. The results show that the main phases of coating are TiC, TiB2 and α-Fe. The excellent metallurgical bonding is formed between the composite coating and substrate. The coating is uniform, continuous and almost defect-free and the particles are dispersively distributed in the cladded coating. Moreover, the formation mechanism was investigated. With the increase of the content of TiC+TiB2, the micro-hardness and wear resistance are also improved at the room temperature under normal atmosphere conditions.