WC-Co cemented carbide with plate-like WC grains was prepared by adding 2%, 4%η phase powders and the equimolar carbon black to a ball-milled WC-10Co batch through traditional powder metallurgy process. The carbonization reaction ofη phase, effect of addition amount and the milling time in the batch ofη phase powders on the microstructure and properties of cemented carbide were studied. The results indicate that small additions ofη phase and equimolar carbon black help the development of plate-like grains, the number of plate-like WC grains increases as the amount ofη phase powders increases, and when the total milling time is constant, the distribution of plate-like WC grains is more uniform as the milling time in the batch ofη phase powders increases. This kind of plate-like WC grain is produced from the twined WC which forms from the carbonization reaction between 950℃ to 1 200℃ ofη phase and the C atoms that spread from the matrix, and the carbonization rate ofη phase is the key factor that influence the morphology of twined WC. The density of the cemented carbide with plate-like WC grains is the same as the traditional one which has the equal content of Co, while the hardness, transverse rupture strength, and fracture toughness are increased by 0.7%, 6% and 17%, respectively.%通过向WC-10Co混合粉末中加入2%和4%质量分数的η相粉末和等摩尔量的炭黑，经过传统的粉末冶金工艺制备含板状WC晶粒的硬质合金，研究η相碳化反应过程以及η相粉末加入量、η相粉末在基体中球磨时间对合金组织与性能的影响。结果表明：加入少量的η相粉末及等摩尔量的工业炭黑后，WC-10Co中的WC晶粒出现了明显的板状特征，随η相粉末加入量增多，板状WC晶粒数量增多；在总球磨时间不变的前提下，随η相粉末在基体中球磨时间增加，板状WC晶粒的分布越来越均匀。所得到的板状WC晶粒是η相在950～1200℃之间与WC-Co基体中扩散来的C原子碳化反应后生成不同形貌的WC孪晶得来的，且碳化速度是影响WC孪晶形貌的关键因素。相对于相同Co含量的传统硬质合金，板状WC晶粒均匀分布的硬质合金密度基本保持不变，硬度提高0.7%，强度提高6%，断裂韧性提高17%。
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