Cavitation erosion resistance of ZrC nanoceramic coating

A ZrC nanoceramic coating was prepared on the bare 316 stainless steel for improving the cavitation erosion resistance by the double glow discharge sputter technique. The phase constitution and surface microstructure of the ZrC nanoceramic coating were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscopy. A 10-mu m-thick ZrC nanoceramic coating exhibited equiaxed grains with an average grain size of 9 nm. The adhesion strength and mechanical properties for the ZrC nanoceramic coating were evaluated by scratch test and nanoindentation. The hardness value of the ZrC nanoceramic coating was about four times that of the uncoated 316 stainless steel. The cavitation erosion behavior of the ZrC nanoceramic coating in tap water was characterized by the combination of an ultrasonic vibration system with an electrochemical workstation. The volume loss, erosion depth, scanning electron microscope morphology, and electrochemical test were adopted to assess the surface damage of the ZrC nanoceramic coating. The results show that the volume loss of the ZrC nanoceramic coating is 0.53 mm(3), which is only 46% of the 316 stainless steel (1.14 mm(3)) after cavitation test, and erosion damage of the ZrC nanoceramic coating is significantly decreased as compared to the uncoated 316 stainless steel. The electrochemical test results also indicate that the ZrC nanoceramic coating shows higher corrosion resistance than the 316 stainless steel under cavitation erosion condition. Thus, the ZrC nanoceramic coating can be adopted to enhance the cavitation erosion resistance of the 316 stainless steel.