Properties of TiN-matrix coating deposited by reactive HVOF spraying.

TiN-matrix coating was prepared by reactive high velocity oxygen fuel (HVOF) spraying on carbon steel based on the self-propagating high temperature synthesis (SHS) technique in air. The phase composition, structures, and properties of TiN-matrix coating were analyzed using XRD, EDS, SEM and Vickers microhardness equipment. The anti-corrosion property in nearly neutral 3.5 wt% NaCl electrolytic solution was measured. The Weibull distribution of Vickers microhardness at different loads and their linear fitting were analyzed. The apparent fracture toughness of the coating was also calculated. The coating is composed of main phases (TiN, TiN_0.3), minor phases (Ti₂O₃, TiO₂), and porosity. The anti-corrosion property of an HVOF-sprayed TiN-matrix coating in electrolytic solution is superior to that of AISI 316L stainless steel. The microhardness values from 1137HV_0.05 to 825HV₁ are relatively high and have indentation size effect (ISE). With the increment of m, which increases with the increment of applied load, the microhardness values are more concentrated. The average value of apparent fracture toughness K _IC is $$ 4.62\,\hbox{MPa} \cdot m^{{\frac{1} {2}}} $$. It is higher than that of reactive plasma sprayed (RPS) TiN coating, which reflects the good toughness of a TiN-matrix coating deposited by reactive HVOF spraying. [ABSTRACT FROM AUTHOR]