摘要：利用烧结破碎法,以超细晶粒WC粉、Co粉为原料制备了WC-17%Co热喷涂粉末。用X-射线衍射和扫描电子显微镜对粉末的形貌和结构进行了研究,讨论了烧结温度、有机粘结剂、碳粉对粉末特性的影响。实验结果表明:将有机粘结剂添加到粉末中后,可有效地阻止超细WC/Co粉烧结时η相(Co₃W₃C、Co₆W₆C)的出现;除极少量碳溶于粘结相Co中外,碳主要以游离态形式存在,可抑止粉末热喷涂时WC的分解;制备超细WC-17%Co热喷涂粉末适宜的烧结温度是在1250℃左右。

关键词：超细晶粒；WC-Co粉；相结构；热喷涂；耐靡涂层

Abstract：WC-17%Co feedstock powder for the purpose of thermal spray was prepared by the method of sinter-crushing.Ultra-fine tungsten carbide powder and cobalt powder were used as starting materials.The influences of sintering temperature, organic binder and carbon on the morphology and phase composition of the WC/Co powder were studied by X-ray diffraction and scanning electron microscopy.Experimental results show that the addition of an organic binder into the powder before sintering is useful in preventing the formation of harmful η phases(Co₃W₃C、Co₆W₆C). Besides the very limited dissolution in the binder phase of Co, the added carbon mainly exists in the form of free carbon that can inhibit the decomposition of WC during subsequent thermal spraying. The suitable sintering temperature for preparing ultra-fine grain WC/Co feedstock powder for thermal spray is approximately 1 250 ℃.

Keywords：ultra-fine grain;WC-Co powder;phase composition;thermal spraying;wear resistance coating