(浙江大學 材料科學與工程系， 杭州 310027)
摘 要: 研究了碳納米管對納米WC粉體熱穩(wěn)定性的影響， 對加入1%（質量分數(shù)）碳納米管的復合納米WC粉體進行了差示掃描量熱（DSC）和X射線衍射實驗和分析， 測定了不同退火溫度下復合粉體的晶粒尺寸， 由Kissinger方程計算了復合粉體的晶粒長大激活能。 結果表明： 1%碳納米管的加入對納米WC粉的熱穩(wěn)定性產生了顯著影響， 晶粒長大激活能增加了21％， 不同退火溫度下的晶粒長大受到了明顯的阻礙； 在800~1000復合粉退火試樣中發(fā)生了W2C 轉變?yōu)?WC的擴散相變， 消除了硬脆W2C相，有利于改善納米WC的綜合力學性能。
關鍵字: 熱穩(wěn)定性；納米WC硬質合金； 碳納米管； 復合材料
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
