Z. Ding, H. Zhao, Y. Zhang, Wuhan University of Technology, Wuhan, China
Cavitation erosion is one of the major problems of hydraulic equipment and may cause the equipment to reduce power and then to stop working. Now with the study of nanomaterials, some special properties of nanostructured coatings are recognized and HVOF nanostructured WC-12Co coating may possess far more excellent potential to protect equipment from cavitation erosion than the conventional HVOF coatings. In the paper nanostructured and conventional coatings were deposited by HVOF. Resistance of the coatings to cavitatin erosion was studied by ultrasonic vibration cavitation equipment. Cavitation holes were observed by SEM and caviation mechanisms were explored. The results showed that nanostructured coatings demonstrated more excellent performance in caviation erosion, volume loss is 1/3 fewer than the conventional one. Nanostructure in the coating is an important factor, which influence the resistance of coatings to caviation erosion.Keywords: HVOF; Nanostructured coatings; cavitation erosion
Summary: Reseach results show:(1) Microstructures of nanostructured WC-12Co coatings deposited by HVOF are dense and possess little porosity;
(2) Nanostructured coatings demonstrated more excellent performance in caviation erosion and the volume-loss is 1/3 fewer than the conventional one;
(3) Nanostructure in coatings is main factor in resistance to cavitation erosion, which increase the coating hardness, toughness and prevent crack to enlarge rapidly.
