Mechanical Properties of WC-8Co Wear-Resistant Coating on Pump Impellers Surface by Electro- Spark

A WC-8Co cladding coating was prepared on the surface of 1Cr18Ni9Ti stainless steel by electro-spark cladding technique combined with an original spiral reciprocating processing method, to improve the capacity of anti-cavitation, anti-abrasion on the surface of flow parts of the pumps. The morphology, the microstructure, the microhardness and the wear resistance of the cladding coating were investigated by means of scanning electron microscopy (SEM), microhardness test and friction and wear test. The results indicate that the cladding coating is uniform, continuous, compact, with no obvious cracks and holes, and there is no clear dividing line and a metallurgical bonding is presented between cladding coating and substrate material. The highest microhardness HV0.3 is 18 920 MPa and the average hardness HV0.3 of the cladding coating is 17 950 MPa, which is about 6 times higher than that of the substrate (2600 MPa). The wear resistance of the cladding coating is 3.75 times of the substrate and the main wear mechanism is adhesive and abrasive wear.