Cavitation Erosion of NiTi Composite Coating Deposited by Atmospheric Plasma Spraying

Abstract

The surface properties and cavitation erosion performance of NiTi/NiCr-75%Cr 3 C 2 composite coatings on AISI 304 stainless steel substance by atmospheric plasma spraying (APS) at different hydrogen gas flow rate were investigated. Composite coatings were characterized for microhardness. Microstructure of the cross section of composite coatings were investigated by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). Caivation erosion test was finished by ultrasonic stretching vibration caviation test machine. The results show that when the hydrogen gas flow rate is 3L/min and 6L/min, the microhardness of coatings are respectively 640 HV and 730 HV at a load of 100 g and a dwell time of 15 s condition, and the composite coatings by APS generates porosity and were oxidized. The cavitation erosion resistance of composite coatings is better than that of nodular cast iron. As the hydrogen gas flow rate increases, the microstructure of composite coating deposited by APS has lower porosity, and the better cavitation erosion resistance.