Microstructure and cavitation erosion behavior of FeNiCrBSiNbW coating prepared by twin wires arc spraying process

FeNiCrBSiNbW coatings were prepared by twin wires arc spraying (TWAS) process. The microstructure and phases were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and differential scanning calorimeter (DSC). FeNiCrBSiNbW coating with compact structure and less oxide consisted of amorphous phase and some of α-(Fe, Cr) nanocrystalline phase. The crystallization temperature was 545 °C after a wide supercooling liquid region of 51 °C. FeNiCrBSiNbW coating had a hardness value of 919 ± 49 Hv0.1, much higher than that of the 316 L coating (239 ± 19 Hv0.1). The cavitation erosion behavior of FeNiCrBSiNbW coating and 316 L coating was investigated in distilled water. FeNiCrBSiNbW coating exhibited higher cavitation erosion resistance than that of the 316 L coating, due to the amorphous/nanocrystalline structure, less oxide and higher hardness. It revealed that FeNiCrBSiNbW coating was destroyed mainly in the form of delamination and the cavitation erosion cracks initiated at the edge of pores and the interface area around the un-melted particles.