Microstructure and Properties of HVOF Sprayed Co-TiB2 Coatings

Co-TiB2 coatings were deposited by high velocity oxy-fuel (HVOF) process with different spray parameters. Two cermets were perared with the following target compositions namely, Co-75%TiB2 and Co-50%TiB2. The microstructure characteristics of powders and coatings were observed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), whilst microhardness and abrasive wear tests were performed on the coatings to evaluate their performance. Results showed that the coatings are dense and have excellent combination with substrate. Coatings consisted primarily of TiB2 particles in a cobalt-based binder phase. The Co-75%TiB2 coating had a lower wear rate than Co-50%TiB2. The microhardness (HV0.2) of Co-75%TiB2 is 789, and that of Co-50%TiB2 is 763.