Microstructure and Properties of TiC-TiB_2 Reinforced Ni-Based Coatings Prepared by High Velocity Oxygen Fuel Spraying

Two types of nickel-based coatings reinforced with TiC-TiB2 were prepared on AISI-1045 steel substrate using high velocity oxygen fuel (HVOF) spray. The microstructure and properties of the coatings were investigated, using Ni60 coating as a reference. Results showed that the raw material powders containing Ti-B4C reaction ingredients had a much higher flame temperature than Ni60 powder, and the Ni-based coating reinforced with TiC-TiB2 had significantly higher microhardness and wear resistance than Ni60 coating. Moreover, TiC-TiB2 ceramics phase with fine grain size was uniformly distributed and well adhered in metallic matrix in the coating prepared from agglomerated TiC-TiB2-Ni raw material powders, contributing to enhancing the strength, hardness, and wear resistance of the coating. While in the coating prepared from the agglomerated powders of Ti-B4C mechanically mixed with Ni60 powders, the ceramics phase and metallic phase showed obvious segregation, leading to decreased adhesion strength and wear resistance of the coating as well.