烧结破碎法制备超细晶粒WC-12%Co热喷涂粉末

Preparation of ultra-fine grain WC-12%Co feedstock powder for thermal spraying by sinter-crushing method

利用烧结破碎法,以粗颗粒(Fsss粒度为3.56μm)和超细颗粒(Fsss粒度为0.68μm)WC粉、Co粉为主要原料制备了WC-12%Co热喷涂粉末。用X-射线衍射和扫描电子显微镜(SEM)对粉末的形貌和结构进行了研究,讨论了烧结温度、颗粒大小、有机粘结剂、碳粉对粉末特性的影响。实验结果表明:原始粉末颗粒大小影响粉末的烧结状态和相组成;添加有机粘结剂能促进粉末的烧结;添加碳粉(主要以游离态存在),可有效抑制超细WC粉烧结时η(Co3W3C)等有害相的出现;1 250℃是制备超细WC-12%Co热喷涂粉末较好的烧结温度。

WC-12%Co feedstock powder for thermal spraying was prepared by sinter-crushing method. 3.56 μm coarse and 0.68 μm ultra-fine tungsten carbide powders and cobalt powder were used as main raw materials. The influences of the sintering temperature, organic binder and carbon content on the morphology and phase composition were investigated by X-ray diffraction and scanning electron microscopy. The experimental results show that the particle size of starting WC powder significantly influences sintering process and phase constituent , organic binder added into the raw powders promotes sintering process, and the added carbon exists mainly in free state in the prepared powder and is effective in preventing the formation of η（Co2W2C） and other non- WC phases. It is founded that 1250 ℃ is the better sintering temperature to prepare ultra-fine grain WC-12 %Co feedstock powder for thermal spraying.