(浙江大学 材料科学与工程系， 杭州 310027)
摘 要: 研究了碳纳米管对纳米WC粉体热稳定性的影响， 对加入1%（质量分数）碳纳米管的复合纳米WC粉体进行了差示扫描量热（DSC）和X射线衍射实验和分析， 测定了不同退火温度下复合粉体的晶粒尺寸， 由Kissinger方程计算了复合粉体的晶粒长大激活能。 结果表明： 1%碳纳米管的加入对纳米WC粉的热稳定性产生了显著影响， 晶粒长大激活能增加了21％， 不同退火温度下的晶粒长大受到了明显的阻碍； 在800~1000复合粉退火试样中发生了W2C 转变为 WC的扩散相变， 消除了硬脆W2C相，有利于改善纳米WC的综合力学性能。
关键字: 热稳定性；纳米WC硬质合金； 碳纳米管； 复合材料
and carbon nanotubes
（Department of Materials Science and Engineering,
Zhejiang University, Hangzhou 310027, China）
Abstract:Thermal stability for the composite of 99% nanocrystalline WC and 1% carbon nanotubes(in mass fraction) was experimentally studied using differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The composite samples were annealed at different temperatures. The grain sizes of the composite samples before and after annealing were measured by XRD and the activation energy for grain growth was calculated using Kissinger equation. In the composite samples, thermal stability of the nanocrystalline WC powder is obviously influenced by the addition of 1% carbon nanotubes. The activation energy for grain growth increases by about 21% and the grain growth under different annealing temperatures is slowed down. In addition, a diffusive phase transition from W2C to WC is observed during the annealing process of the composite samples at 800～1100, which is beneficial to the improvement of mechanical properties of nano-sized WC.
Key words: thermal stability; nanocrystalline WC hard alloys; carbon nanotubes; composite
