Abstract
Conventional, multimodal and nanostructured WC-12Co coatings with different WC sizes and distributions were prepared by high velocity oxy-fuel spray (HVOF). The micrographs and structures of the coatings were analyzed by scanning electron microscope (SEM), X-ray diffractometer (XRD) et al. The porosity, microhardness and fracture toughness of the WC-Co coatings were measured. The coating resistance to cavitation erosion (CE) was investigated by ultrasonic vibration cavitation equipment and the cavitation mechanisms were explored. Results show that there is serious WC decarburization in nanostructured and multimodal WC-Co coatings with the formation of W2C and W phases. The nanostructured WC-Co coating has the densest microstructure with lowest porosity compared to the other two WC-Co coatings, as well as the highest fracture toughness among the three coatings. It was also discovered that the nanostructured WC-Co coating exhibits the best CE resistance and that the CE rate is approximately one-third in comparison with conventional coating.
Highlights
Cavitation erosion (CE) widely exists in the components of fluid equipment, such as marine rudder blades, propellers, and turbine impellers
Nanostructured, conventional and multimodal WC-12Co (88 wt % WC-12 wt % Co) powders were chosen as feedstock in this study and they were marked as NP, CP, and MP, respectively
The conventional, multimodal and nanostructured WC-12Co coatings were fabricated by a high velocity oxy-fuel spray (HVOF) system (JP5000, Praxair, Inc., Indianapolis, IN, USA) and they were marked as CC, MC and NC, respectively
Summary
Cavitation erosion (CE) widely exists in the components of fluid equipment, such as marine rudder blades, propellers, and turbine impellers. WC-Co coatings, especially with nano-sized WC particles, have already been successfully utilized in some wear-resistant equipment [8,9]. Compared with the conventional WC-Co coatings, multimodal WC coatings offer a denser structure, higher abrasive wear resistance and anti-cavitation performance [24,25,26]. By comparing the microstructure and surface properties of conventional and nano WC-Co coatings, Zhao et al [27] concluded lower porosity, higher microhardness and fracture toughness could result from the nano coatings. The CE mechanisms of the coatings were proposed in terms of the formation and propagation of microcracks These results can provide valuable references for WC-Co anti-cavitation coating design and application
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
