The composite Fe–Ti–B–C Coatings by PTA powder surfacing process

For the purpose of reduction of Fe–B–C coatings high brittleness, the composite Fe–Ti–B–C coatings were developed by plasma transferred-arc (PTA) powder surfacing process with a powder mixture of B4C and Fe–Ti alloy. The microstructure, hardness and cracking resistance of these coatings were investigated in this paper. The experimental work enables the following findings to be reached: (i) The needle-like TiB2 whiskers could be synthesized in situ using the plasma transferred-arc powder surfacing process in the composite Fe–Ti–B–C coatings. (ii) The size, shape and volume fraction of TiB2 whiskers in the composite coating are greatly dependent upon powder composition (contents of B, Ti elements and the ratio of B/Ti) and the arc energy density used. The average ratio of length/width for the synthesized TiB2 whiskers increases with increasing arc energy density and ratio of B/Ti elements in this coating. (iii) Both the hardness and cracking resistance of the Fe–B–C coating could be improved by the formation of TiB2 whiskers.