超细碳化钨-钴硬质合金的原子力显微镜研究

AFM Study of Ultrafine Tungsten Carbide-Cobalt Cemented Carbide

以液相复合-连续还原碳化方法制备的纳米碳化钨-钴复合粉末为原料,采用低压烧结制备了性能优良的超细碳化钨-钴硬质合金。运用原子力显微镜(AFM)对超细碳化钨-钴硬质合金的表面形貌进行了观察、缺陷和粒度分析,同时对合金的力学性能进行了测试。结果表明,采用低压烧结获得的烧结试样的洛氏硬度HRA≥93.5,抗弯强度TRS≥3300MPa,平均晶粒度<220nm。制备了具有高强度、高硬度的超细碳化钨-钴硬质合金。纳米碳化钨-钴复合粉末制备的超细硬质合金组织结构均匀,但局部仍然存在着组织缺陷,分析了产生缺陷的机理。

Nanocrystalline tungsten carbide-cobalt composite powders prepared spray pyrogenation-continuous reduction and carbonization technology are consolidated by sinterhip. The topographies, grain size distribution and microstructure limitation of ultrafine tungsten carbide-cobalt cemented carbide are observed using atomic force microscope （AFM）, and mechanical properties are also investigated. Results show that ultrafine tungsten carbide-cobalt cemented carbide with average grain size of less than 220nm, transverse rupture strength （TRS）of more than 3300 MPa and Rockwell A hardness of more than 93. 5 is achieved. Although microstrueture of ultrafine cemented carbide prepared by nanocrystalline tungsten carbide-cobalt composite powder is homogeneously, but there are a lot of microstructure limitation, and this paper analyses their forming mechanisms.