WC-Co硬质合金制备中铝元素对钨产品的影响  

Effect of aluminum element on tungsten products in the preparation of WC-Co cemented carbide

作　　者：朱红波[1] 杨欣[1] 谭敦强[1] 李亚蕾[1] 何文[1] 汤斌兵[1] 

机构地区：[1]南昌大学材料科学与工程学院,南昌330031

出　　处：《粉末冶金材料科学与工程》2016年第2期202-208,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(51564036);国家高技术研究发展计划(863计划)资助项目(2012AA061902)

摘　　要：在仲钨酸铵(ammonium paratungstate,APT)中添加一定量的Al(NO_3)_3·9H_2O,制得Al含量(质量分数)为1.0%的APT-Al复合粉末。经煅烧、还原、碳化和液相烧结,分别得到含Al的W粉、WC粉及WC-Co硬质合金等钨产品。通过X线衍射(XRD)、场发射扫描电镜(FESEM)和高分辨透射电镜(HRTEM)对W及WC粉的形貌及结构进行分析,并分析Al元素在几种钨产品中的分布,研究WC-Co硬质合金制备过程中Al元素的相演变情况,以及Al元素对各阶段钨产品组织形貌与结构的影响。结果表明:在WC-Co硬质合金的制备过程中,Al元素经历Al_2(WO_4)_3—AlWO_4—Al_4C_3的相演变。Al_2(WO_4)_3和AlWO_4阻碍W颗粒通过"挥发-沉积"机制而长大,导致钨粉细化;Al_4C_3颗粒分布于WC颗粒之间,并阻碍细小WC颗粒通过晶界迁移而长大;WC-Co硬质合金中的Al元素主要分布在Co粘结相中以及细小WC颗粒聚集处,使得合金的致密度、硬度和断裂韧性都降低。APT-Al composite powder（1.0% Al） was obtained by adding Al（NO3）3 into ammonium paratungstate（APT）. The Al-doped W powder, WC powders and WC-Co cemented carbide were prepared by calcination, reduction, carbonization and liquid phase sintering. The morphology and microstructures of W and WC powders were characterized by X-ray diffraction（XRD）, field-emission scanning electron microscopy（FESEM） and high resolution transmission electron microscopy（HRTEM）. The distributions of Al element in W, WC and WC-Co cemented carbide were analyzed by energy dispersive spectroscopy（EDS）. The phase evolution of Al element during the preparation process of WC-Co cemented carbide and its influence on the morphology and microstructures of tungsten products were also studied. The results show that Al element experiences the phase evolution of Al2（WO4）3—AlWO4—Al4C3 during the preparation processes of WC-Co cemented carbide. The growth of W particles is inhibited by Al2（WO4）3 and AlWO4 during the hydrogen reduction process of tungsten oxide, resulting in refined tungsten particles. The Al4C3 particles distribute between WC particles, which can hinder small WC particles to grow via grain boundary migration. In addition, the Al element exists in the Co binder phase and the collection region of small WC particles, resulting in the decrease of density, hardness and fracture toughness of WC-Co cemented carbide.

关 键 词：AL元素 钨 碳化钨 WC-CO硬质合金 相演变 

分 类 号：TF125[冶金工程—粉末冶金]