超音速火焰喷涂两种WC-17%Co涂层的组织和性能研究

采用超音速火焰喷涂法制备纳米和普通WC-17%Co涂层,借助于SN-3400型扫描电镜(SEM)、D8型X射线衍射仪(XRD)、HXD-1000TM型显微硬度计、SHT4605型拉伸试验机和TRB型球盘磨损试验机对涂层组织结构、相组成、显微硬度、结合强度及耐磨性能进行了分析.结果表明,两种WC-17%Co涂层形成过程中WC发生了分解,并形成了W2C、W和CoxWyCz(Co3W3C、Co3W9C4)等一些新相,纳米涂层的组织形态明显好于普通涂层,组织晶粒细小,WC晶粒保持在120~150 nm的纳米尺度范围;纳米涂层的显微硬度、结合强度和耐磨性都高于普通涂层,相比之下,纳米涂层的显微硬度、结合强度比普通涂层高出近30%,在相同的试验条件下普通涂层的磨损体积是纳米涂层的2倍.

Research on Structure and Properties of Two WC-17 %Co Coatings Deposited by High Velocity Oxygen Fuel Spraying

WC-17%Co coatings were deposited by High Velocity Oxygen Fuel（HVOF） spraying with nano-struc- tural and conventional powder feedstock. The surface morphology, microstructure and worn surface morphologies of the coating were analyzed by SN-3400 scanning electron microscopy. The phase composition of the coating was determined by X-ray diffraction. The micro-hardness of the coating was evaluated on an HXD-1000TM micro- hardness instrument. The adhesive strength of the coating was investigated on an SHT4605 universal testing ma- chine. The wear properties of the coating were investigated on an TRB-ball-on-disc-wear tester without lubrica- tion. The results show that the microstrncture of the nanostructured coating was better than that of the convention- al coating. In the process of the two WC-17%Co coatings preparation,some new phases,such as W2C, W, Cox WyCz（Co3W3C, Co3W9C4） were created. The grain size of WC was in the range of 120-150nm. The micro- hardness, adhesive strength and wear properties of nanostrnctured coating were better than that of conventional coating.