(1. 中南大学 粉末冶金国家重点实验室，长沙 410083；2. 湖南顶立科技有限公司，长沙 410111)
摘 要: 以碳酸钴为原料，采用氢气还原法在带式无舟皿连续还原炉中制备超细球形钴粉。考察还原温度和还原时间对钴粉粒度的影响。结果表明，在420~460 ℃还原180 min左右，可以制备费氏粒度为0.9 μm左右的超细球形钴粉。采用二氧化碳气体钝化处理技术降低了钴粉的氧含量。采用制备的钴粉为超细晶粒硬质合金的粘结剂，用低压烧结工艺制备出钴相高度分散、晶粒均匀的超细晶粒YG10硬质合金。其晶粒度为0.4 μm，矫顽磁力达38.0 kA/m，硬度大于93.0 HRA，抗弯强度高于3 700 MPa。
关键字: 超细球形钴粉；气体钝化；超细晶粒硬质合金
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;2. Hunan Denli Technology Co. Ltd, Changsha 410111, China）
Abstract:Ultra-fine cobalt powder was prepared by the reduction of carbonate using a belt continuous boat-less reducing furnace in hydrogen. The influences of reduction temperature and time on the particle size of cobalt powder were studied. Ultra-fine spherical cobalt powder with particle size of around 0.9 μm was prepared at 420−460 ℃ for 180 min. The influence of CO2 passivation treatment on the oxygen content of cobalt powder was discussed. Ultra-fine WC-10Co cemented carbides were prepared by vacuum/pressure sintering technology using the obtained cobalt powder as raw binder material. YG10 ultra-fine cemented carbide was prepared with uniform distribution of cobalt phase, homogeneous grain size of around 0.4 μm, hardness equal to HRA93.0, bending strength equal to 3 700 MPa and coercive force equal to 38.0 kA/m.
Key words: ultra-fine spherical cobalt powder; CO2 passivation treatment; ultra-fine cemented carbides
