Influence of CeO2 on tribological behaviour of TiC/Fe-based composite coating

摘要

The TiC/Fe-based composite coating with different CeO2 content was fabricated on the Cr12MoV steel by laser cladding. The microstructure of cladding layers all had the planar grain, columnar grain, cellular grain, and equiaxed grain. Without adding rare earth, TiC ceramic particles had the irregular shape, large size difference, and a certain degree of reunion. Appropriate rare earth could effectively spheroidise and refine ceramic particles, and made the distribution uniform. Excessive rare earth could cause the burning loss of ceramic particles, inhibit the formation of second precipitated phases, and the reunion of particles occurred again. The Ti element, decomposed from TiC ceramic particles, combined with the Fe and Cr elements to form the Ti/Fe/Cr or Fe/Ti/Cr compounds. Hence, the metallurgical bonding between particles and cladding layer metal was increased. The micro-hardness and wear properties of the cladding layer had a close relation with the shape, size, distribution, and the form of TiC ceramic particles.