Abrasive Resistance of Arc Sprayed Coatings with a WC Ceramic Phase

Iron-based composite coatings were deposited on mild steel substrate by arc spraying cored wire with WC-CoNi ceramic powders. The abrasion wear properties were evaluated using a examined MLS-225 wet sand/rubber wheel tester. The microstructure, phase compositions and worn surface of the coatings were examined by means of optical, scanning electron microscopy and X-ray diffraction. The results show that the coatings with WC ceramic phases exhibited better abrasive wear resistance and about 9 times higher than that of the Q235 mild steel. The hardness and abrasive resistance of the coatings increased with increasing WC content in the cored wire. The abrasive wear resistance of the coating reduced when WC content was more than 25%. The metallic matrix of the coatings, due to their low hardness, were worn prior to the tungsten carbides. Brittle peeling and micro-ploughing are the major wear mechanism of the coatings. WC, FeaB ceramic phase with higher hardness played a role to resist the abrasion from silica, and thus decreases the abrasion of the coatings.