高能球磨合成纳米WC-Co复合粉末的特性

Characterizations of High Energy Ball Milled Nanocrystalline WC-Co Composite Powders

采用变转速多次循环高能球磨工艺在 3 2min制备出了平均晶粒尺寸约为 2 5nm的纳米WC 10Co 0 .8VC 0 .2Cr3C2 (重量分数 )复合粉末 ,并用化学元素分析、XRD ,TEM ,DTA对纳米WC Co复合粉末的特性进行了表征和分析。结果表明 ,变转速多次循环高能球磨工艺制备的纳米WC Co复合粉末 ,化学成分合格 ,杂质含量低 ,球磨效率高 ;球磨过程是一个晶粒逐渐细化的过程 ,同时也是一个晶格畸变逐渐增加、粉末体系能量逐渐增大的过程 ;球磨得到的WC Co纳米复合粉末颗粒形貌基本为球形 ,粒径分布较宽 ,颗粒中存在着一些团聚体 ,平均颗粒尺寸约为 5 0nm ;纳米WC 10Co 0 .8VC 0 .2Cr3C2 (wt%)复合粉末的共晶点约为 12 80℃。纳米复合粉末中W ,Co ,V ,Cr元素分布均匀弥散。

Nanocrystalline WC 10Co 0.8VC 0.2Cr 3C 2 (wt%) composite powders with mean grain size of 25 nm were prepared in 32 min by high energy ball milling with variable rotation rate and repetitional circulation process. The as prepared powders were analyzed and characterized by chemical analysis, X ray diffraction (XRD), transmission electron microscopy (TEM), and differential thermal analysis (DTA). The results show that high energy ball milling with variable rotation rate and repetitional circulation could be used to produce nanocrystalline WC Co powder composites with high efficiency. The compositions of the powders meet its specification with low impurity content. The mean grain size decreases, lattice distortion and system energy increase with increasing of milling time. There some agglomeration exists in the particless; the grain size distribution is relatively wide. The morphology of nanocrystalline WC Co composite powder displays approximately sphere shape and the mean particle size of the powder is about 50 nm. The eutectic temperature of the nanocrystalline WC 10Co 0.8VC 0.2Cr 3C 2 composites is about 1280 ℃. And the distribution of the elements W, Co, V, Cr is homogeneous in the sintered composites.