论文部分内容阅读
研究了两步碳化工艺对氢还原/碳化制备的纳米WC粉末及其WC-Co合金性能的影响。结果表明,WC粉末的晶粒聚集和异常粗大颗粒主要是由于碳化初期钨颗粒因烧结合并增粗,而钨粉碳化不完全主要是由于碳化后期的温度偏低,利用先低温碳化后高温碳化的两步碳化工艺不仅能够有效抑制纳米颗粒烧结合并增粗,而且可以使钨粉充分碳化,得到颗粒细小、均匀,W2C含量极少的WC粉末;采用1120℃碳化加1180℃碳化的两步碳化工艺制备出的138 nm的WC粉末,W2C含量少于0.5%(质量分数),以其为原料制备的WC-Co烧结体显微组织结构均匀,为超细晶硬质合金,综合性能优良,洛氏硬度HRA高达93.7,抗弯强度高达4380 MPa。
The effects of two-step carbonization process on the properties of nano-WC powders prepared by hydrogen reduction / carbonization and their WC-Co alloys were investigated. The results show that the grain agglomeration and abnormal coarse particles of WC powders are mainly attributed to the sintering and coarsening of tungsten particles during the initial stage of carbonization. However, the incomplete carbonation of tungsten powders is mainly due to the low temperature at the late stage of carbonization, The two-step carbonization process can not only effectively inhibit sintering and coarsening of the nano-particles, but also can fully carbonize the tungsten powder to obtain WC powder with small and uniform particles and little W2C content. The two-step carbonization process with 1120 ° C. carbonization and 1180 ° C. carbonization The prepared WC-WC powder of 138 nm has a W2C content of less than 0.5% (mass fraction), and the WC-Co sintered body prepared from the WC powder has a uniform microstructure and is an ultrafine-grained hard alloy with excellent comprehensive properties. Hardness HRA up to 93.7, bending strength up to 4380 MPa.