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纳米碳化钨钴复合粉体具有重要的工程应用和市场发展潜力。针对纳米碳化钨钴复合粉形貌难以精确控制这一问题,本文以偏钨酸铵(AMT)、可溶性钴盐、有机碳源为原材料,以蒸馏水为溶剂,不添加WC晶粒长大抑制剂,制备钨钴碳混合溶液,再采用喷雾转化(SCP)和连续低温还原碳化法制备了纳米碳化钨钴复合粉;研究了喷雾转化过程中溶液浓度、进料速度、离心转速和转化温度4个关键因素对纳米碳化钨钴复合粉松装密度、WC晶粒度及微观形貌的影响。研究表明:通过喷雾转化法制备的纳米碳化钨钴复合粉呈空壳球形结构,Co相发生熔化使大多WC被粘结在一起,WC颗粒之间存在明显的烧结颈,颗粒表面存在大量孔隙,部分颗粒存在破裂现象;WC平均晶粒度小于200 nm;离心转速是影响粉末松装密度、WC晶粒度及颗粒形貌的最主要因素;离心转速越大,复合粉末颗粒越小,松装密度越大;同时转化温度越高,WC晶粒度越小,复合粉末颗粒越易破裂。
Nano-tungsten carbide cobalt composite powder has important engineering applications and market potential. In order to solve the problem that it is difficult to precisely control the morphology of nano-tungsten carbide-cobalt composite powder, this paper takes ammonium metatungstate (AMT), soluble cobalt salt and organic carbon source as raw materials and distilled water as solvent without addition of WC grain growth inhibitor , Preparing a tungsten-cobalt-cobalt mixed solution, and then preparing a nano-tungsten carbide-cobalt composite powder by spray transformation (SCP) and a continuous low-temperature reductive carbonization method. The concentration of the solution, the feed speed, the centrifugal speed and the transition temperature during the spray conversion process were studied Effect of Key Factors on Bulk Density, WC Grain Size and Micromorphology of Nano-WC Powders. The results show that the nano-WC-Co composite powder prepared by spray-transformation has the shape of an empty shell and the Co phase melts to bond most of the WC together. There is a clear sintering neck between the WC particles and a large number of pores exist on the surface of the particles, Some particles have rupture phenomenon; average grain size of WC is less than 200 nm; centrifugal speed is the most important factor that affects powder bulk density, WC grain size and particle morphology; the larger the centrifugal speed, the smaller the composite powder particles, loose The greater the density; at the same time the higher the conversion temperature, the smaller the WC grain size, the more easily broken composite powder particles.