Wear-resistant coating of Fe-based alloy by plasma cladding on cast iron

By plasma cladding technology a wear-resistant coating with metallurgical bonding to substrate was prepared on boron cast iron with Fe-based alloy powder.The microstructure of the bondng coating was investigated by optical microscope (OM), scanning electron microscope (SEM), X-ray diffractometer (XRD).The microhardness was tested by microhardness tester.The wear resistance performance of the coating was evaluated on a MM-200 block-on-wheel sliding wear tester.The results show that the coating has a microstructure consisting of primary phase (Cr,Fe)₇C₃, α-(Fe,Cr)and Fe₃C, its microhardness varies from 600 HV_0.2 to 1200 HV_0.2.The relative wear resistance of the coating is about 5 times higher than that of boron cast iron substrate under dry sliding wear test conditions, which results from the presence of hard, wear-resistant primary phase (Cr,Fe)₇C₃ and Fe₃C in coating, the solid solution strengthening by large amount of Cr and Si supersaturated in α solid solution, and from the grain size strengthening by rapidly heating and solidification of the coating.