Synthesis of WC composite powder with nano-cobalt coatings and its application in WC-4Co cemented carbide
Synthesis of WC composite powder with nano-cobalt coatings and its application in WC-4Co cemented carbide
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DOI：
10.1016/j.ceramint.2018.03.174
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发表时间：
2018-06
影响因子：
5.2
通讯作者：
R. He;Jianying Wang;Meng He;Hailin Yang;J. Ruan
中科院分区：
文献类型：
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作者：
R. He;Jianying Wang;Meng He;Hailin Yang;J. Ruan
采用溶胶-凝胶法制备了纳米钴包覆碳化钨复合粉末，并将其制备成粗晶WC-4wt%Co硬质合金。采用X射线衍射（XRD）、透射电子显微镜（TEM）和扫描电子显微镜（SEM）分析了复合材料的相组成和显微结构。结果表明，在溶胶-凝胶过程中，WC颗粒完全包裹在CoC 2 O 4层中。以WC-CoC 2 O 4前驱体粉末为原料，在氢气气氛中还原制备了核壳结构的WC-4wt%Co复合粉末。钴涂层的形貌和晶体结构被发现取决于还原温度。化学分析表明，WC-Co复合粉末无污染，成分可控。与球磨WC-Co粉末制备的硬质合金相比，由钴包覆WC复合粉末制备的WC-4wt%Co硬质合金具有细化均匀的显微组织，从而提高了力学性能。横向断裂强度为2249 MPa的硬质合金从钴涂层的WC粉末，相比之下，1871 MPa的由球磨粉末制成的碳化物。
Composite powder of tungsten carbide with nano-cobalt coatings was successful manufactured via a novel sol-gel process, and coarse grained WC-4 wt% Co cemented carbide was produced from the cobalt-coated WC powder. Phase composition and microstructure evaluation were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results revealed that the WC particles were completely encased in the CoC2O4layers by the sol-gel process. Core-shell structured WC-4 wt% Co composite powder was subsequently prepared by reducing the WC-CoC2O4precursor powder in hydrogen atmosphere. The morphology and crystal structure of the cobalt-coating were found to depend on the reduction temperature. Chemical analyses revealed that the WC-Co composite powders were non-contaminated and composition-controllable. WC-4 wt% Co cemented carbide fabricated from the cobalt-coated WC composite powder showed a refined and uniform microstructure, and therefore improved mechanical properties, compared to the cemented carbide made by ball-milled WC-Co powder. The transverse rupture strength was 2249 MPa in the cemented carbide from the cobalt-coated WC powder, compared to 1871 MPa of the carbide made by the ball-milling powder.