Synthesis of TiB2–TiC/Fe nano-composite coating by laser surface engineering

The study explores the synthesis of TiB2 and TiC reinforced Fe-based nano-composite coating by laser surface engineering using Ti, B4C and Fe powder mixture as precursor. The effect of laser scanning speed on the size, morphology, and amount of nano-sized ceramic reinforcements were studied at laser fluence of 1111 J/cm2, 1667 J/cm2 and 3333 J/cm2 respectively. A bimodal microstructure with TiC and TiB2 particles dispersed in fine α-Fe matrix was evolved in the laser processed coatings. Besides, the nature of formation of nano-sized ceramic phase was examined. The laser synthesized nano-composite coating yielded 3–5 times increase in microhardness. It appears that the presence of nano-sized TiB2 and TiC particles coupled with the highly refined α-Fe matrix improves the hardness significantly. This coating offers the potential to increase the hardness and toughness simultaneously for developing wear-resistance coatings.

► In situ TiB2-TiC/Fe nano-composite coating can be synthesized by laser surface engineering. ► Correlation between microstructure evolution and processing parameters has been established. ► Identification of in situ evolved phase constituents and their morphologies is provided. ► Nano-particles coupled with highly refined matrix result in improved hardness of the coating.