低温超音速火焰喷涂纳米WC-10Co4Cr涂层的显微结构和性能

以纳米和微米WC-10Co4Cr粉末为热喷涂粉末,采用低温超音速火焰喷涂（LT-HVOF）和超音速火焰喷涂（HVOF）技术制备了WC-10Co4Cr涂层,采用SEM、XRD、和显微硬度仪等对LT-HVOF WC涂层显微结构和性能进行了表征.结果表明：n-WC涂层、lm-WC涂层的显微结构与普通超音速火焰喷涂WC涂层没有明显的区别,其主晶相为WC; m-WC涂层呈明显的层状结构,涂层中WC颗粒尖端发生了钝化和部分熔化,粒径变小,并形成了WC/的核壳结构;其主晶相为.n-WC涂层显微硬度较lm-WC涂层低,但其韧度高而使涂层的磨损失重最低;m-WC涂层的显微硬度和韧度最低,磨损失重最大.

Microstructure and Properties for LT-HVOF Sprayed NanoWC-10Co4Cr coatingMicrostructure and Properties for LT-HVOF Sprayed Nano- WC-10Co4Cr coating

WC-10Co4Cr coatings were prepared via Low Temperature High Velocity Oxy-Fuel （LT-HVOF） and HVOF with nano and micro WC-10Co4Cr powder as feedstock. Microstructure and properties for the WC coatings were characterized by SEM, XRD, micro hardness tester and etc.. The results show that n-WC and lm- WC coatings have the similar microstructure as conventional HVOF WC coating, and both coatings are comprised by WC crystal phase, while m-WC coating exhibits layered microstructure, and angular WC particles in the coating become smaller, blunt and even partly melted, and WC/W2C shell structure is formed. The primary crystal phase for m-WC coating is W2C. n-WC-coating owns lower micro-hardness than that of lm-WC coating, while the highest fracture toughness for n-WC makes the !owest wear mass loss. The lowest micro-hardness and fracture toughness of m-WC coating leads to greatest wear mass loss.