Plasma sprayed TiB2-Ni cermet coatings: Effect of feedstock characteristics on the microstructure and tribological performance

In this work, TiB2-Ni cermet coating was deposited by atmospheric plasma spraying using two kinds of feedstock, namely agglomerated powder and clad powder. The microstructure and the phase composition of the powder, as well as the sprayed coating were analyzed. The microhardness (Hv) and the fracture toughness (KIC) of the coating were also evaluated. The results showed that the phenomenon of TiB2 particle's rebounding in deposition and the dissolution of TiB2 were closely related to the feedstocks' characteristic, e.g. TiB2 particle size, binder content and its morphology, which played an important role on the coating microstructure and its mechanical properties. The tribological performance of the coating was also assessed using a linear reciprocating friction tester with GCr15 counterpart. The coating deposited from agglomerated and sintered TiB2-40 wt.% Ni powder presented better tribological properties, i.e. low friction coefficient and wear rate.