Comparison of Microstructure and Properties of In-Situ TiN- and WC-Reinforced NiCrBSi Composite Coatings Prepared by Plasma Spraying

In this study, NiCrBSi-30 wt.% TiN composite (NTC) coating was produced on carbon steel via plasma spraying, with NiCrBSi-30 wt.% WC composite (NWC) coating as the comparison object. The microstructure and phase constituents of the composite coatings were characterized using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) techniques, transmission electron microscopy (TEM) and x-ray diffraction (XRD). Atomic force microscopy (AFM) was used to measure electronic work functions. The microhardness and wear performance of coatings were also investigated. The average microhardness of the NTC and NWC coatings was 1000 HV and 850 HV, respectively. In addition, the NTC coating had a wear volume loss of 0.8118 mm(3), less than 1.4772 mm(3), the volume loss of the NWC coating. This was due to the presence of TiN in the form of nanograins in the composite coating and tighter binding to the matrix.