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.