Preparation and Properties of a Plasma-Sprayed Fe-Cr-B-C Coating

Fe-Cr-B-C wear-resistant coating was prepared by atmosphere plasma spraying. The effects of the spraying current, main gas flow, secondary gas flow, and spraying distance on the microstructure, hardness, and bonding strength of the coating were studied. The results show that the cross-section of the coating is a typical lamellar structure. There are unmelted particles with high hardness in the Fe-Cr-B-C coating, and the hard phase particles are spherical and dispersed. As a result, the microhardness of the Fe-Cr-B-C coating is relatively uniform, within the range of 820-860 HV 0.1 . Spraying process parameters significantly affect the bonding strength of the coating, but have little effect on the microhardness. The matrix of the coating is an oc-Fe phase and the hard phase is mainly a (Fe, Cr)(2) (B, C) phase and a (Fe, Cr)(3) (B, C) phase. Due to the spheroidized coating structure, the wear rate of the FeCrBC coating is only 0.62 x 10(-5) mm(3)/Nm, which is 51% of the 304 stainless steel. The wear mechanism of the Fe-Cr-B-C coating is mainly abrasive wear and fatigue wear.