Phase transformation and wear resistance of submicron structural WC-12Co coatings deposited by HVOF

WC-12Co coatings were deposited by HVOF with cemented carbide feedstock powders including submicron WC particles. The influences of HVOF spraying processes on the microstructures , phase compositions,micro-hardness,and wear resistance of sprayed coatings were investigated by metallographic (OM),scanning electron microscopy(SEM),X-ray diffraction(XRD),micro-hardness tester and wear resistance experiments. A little WC decarburization was observed within all spray parameter levels. It was founded that the degree of decarburization was lower when the C3H8 flow was lower,the oxygen flow was lower, and the stand-off distance was farther. In the dry sliding conditions,the wear processes was began with cutting the soft metal Co,and then leaded to WC particles falling. Finally,the WC particles were as a hard abrasive and then the abrasive wear was dominated. It was detected that Fe element on the surface of coating, which shifted from counter wear ring component.