Plasma spraying and characterization of chromium carbide - nickel chromium coatings

Chromium carbide – nickel chromium powder Cr3C2-25wt.NiCr was plasma sprayed by a water-stabilized system WSP®. A series of experiments with variable feeding distance was carried out. Basic characterization of coatings was done by XRD, SEM and light microscopy plus image analysis. Microhardness was measured on polished cross sections. The main focus of investigation was on resistances against wear in dry as well as wet conditions. The appropriate tests were performed with set-ups based on ASTM G65 and G75, respectively. The influence of spray parameters onto coating wear performance was observed. The results of mechanical tests are discussed in connection with changes in the character of the coating’s microstructure. The results show that for obtaining the best possible Cr3C2-25NiCr coating with WSP® process, from the viewpoint of wear resistance, medium feeding distance is desired and its decrease or increase leads to certain worsening of studied properties.