乙二胺四乙酸在纳米WC/Co复合粉制备中的应用

Application of Ethylene Diaminete Traacetic Acid in the Preparation of Nanophase WC/Co Composite Powder

本文在喷雾转换法制备WC/Co纳米复合粉的基础上,采用乙二胺四乙酸与碳酸钴复合法制备高钴含量的WC/Co纳米复合粉,突破了原有技术的钴含量质量分数上限7%的瓶颈限制。采用DSC-TG分析、SEM分析、XRD分析等方法,对乙二胺四乙酸和碳酸钴的参与反应的机理进行了研究,并确定了采用新工艺制备WC/Co纳米复合粉的相关参数。实验结果表明:乙二胺四乙酸与碳酸钴反应所得有机钴盐为一种溶解度较高的螯合物,在较低温度下煅烧可分解,适用于WC/Co纳米复合粉前驱体溶液中钴含量的调节,避免了Cl-、NO3-等杂质离子的引入。通过新的复合工艺制备得到了适用于高温流态化床生产的前驱体粉末,最终制备得到钴含量质量分数8%的WC-Co纳米复合粉。

In this paper, ethylene diaminete traacetic acid （EDTA） and cobalt carbonate were used to raise the cobalt content during the preparation of WC/Co nano composite powder by spray conversion process, which could break through the cobalt content limit of 7% in the original technology. By DSC-TG, SEM, XRD analysis and other methods, the mechanism how EDTA and cobalt carbonate involved in the reactions was studied, and then the related parameters of new technology for preparing WC/Co nano composite powder were determined. The results show that the organic cobalt salt from the reaction of EDTA and cobalt carbonate has a relatively high solubility, and disintegrates in relatively low temperature. Because of that, it can be applied to the regulation of cobalt content of precursor solution for WC/Co nano composite powder preparation, which can avoid the introduction of Cl-, NO3- and other impurity ions. Through the new complex process, the precursor powder suitable for the production in high temperature fluidized bed is prepared, and finally WC-Co nano composite powder with cobalt of up to 8% mass fraction is achieved.