超音速火焰喷涂微纳米WC-CoCr涂层的性能与空蚀行为

摘要

采用超音速火焰喷涂(HVOF)制备普通微米和微纳米WC-10Co4Cr金属陶瓷涂层,使用光学显微镜、扫描电镜和X射线衍射仪方法分析涂层的组织结构;测量涂层的显微硬度、孔隙率及开裂韧性;采用超声振动空蚀装置在淡水介质中研究WC-10Co4Cr涂层的抗空蚀性能和空蚀行为,并探讨涂层的空蚀机理.结果表明:采用HVOF制备的微纳米WC-10Co4Cr涂层主要由WC相、非晶CoCr相和微量的W2C相组成,涂层中WC未产生明显的脱碳现象;HVOF工艺制备的微纳米WC-10Co4Cr涂层的力学性能和抗空蚀性能明显优于普通WC-10Co4Cr涂层的,在稳定空蚀阶段淡水中微纳米涂层的抗空蚀性能比普通涂层的提高大约1倍.%Micro-nano and conventional WC-10Co4Cr cermet coatings were deposited by high velocity oxygen fuel spraying (HVOF), and the coating structures were investigated by SEM, OM and XRD. Microhardness, porosity and fracture toughness of the coatings were measured. Cavitation erosion resistance of the coatings were carried out by ultrasonic vibration cavitation equipment in fresh water medium, and cavitation behavior was analyzed and the cavitation mechanisms were explored. The results show that the phase compositions of the micro-nano WC-10Co4Cr coating produced by HVOF were mainly composed of WC, amorphous CoCr and a little W2C, and obvious WC decarburization of the coating is not discovered. The mechanical properties and cavitation erosion resistance of the micro-nano WC-10Co4Cr coatings deposited by HVOF are much more superior to conventional one. The cavitation erosion resistance of the micro-nano WC-10Co4Cr coatings sprayed by HVOF is enhanced approximately one times than that of conventional one at stable cavitation period in fresh water.