Influence of spray parameters on the microstructure and properties of high velocity oxy-fuel sprayed multimodal WC-17Co coatings

Two kinds of multimodal WC-17Co powders were deposited on Q235 steel substrate by using high velocity oxy-fuel spray process. The microstructure and worn surface, and the phase compositions of as-sprayed coatings deposited in different conditions were characterized by SEM and X-Ray, respectively. The results show that the morphology of WC particles within as-sprayed coatings were quite different from that within original powders. The flow of propane and oxygen strongly influence the phase constitutions, microstructure and properties of the coatings. The coating deposited in the oxygen flow of 543L/min and propane flow of 24L/min and spray distance of 200mm present no decomposed phase. The hardness, fracture toughness and abrasive wear resistance of the coatings increased with the increasing of oxygen flow or decreasing of propane flow. The microstructure and properties were also influenced by powder manufacture process. The microhardness and abrasive wear weigh loss of the coatings varied from 808±105HV_0.3-1068.5±99HV_0.3 6.05±0.7mg-20.1±0.44mg.