配位沉淀—热分解法制备纤维状银粉
发布时间：2018-08-01 08:38
【摘要】： 超细粉末的用途与性能密切相关,而性能很大程度上取决于其形貌和颗粒尺寸。作为微电子工业关键材料的银粉,人们对其形貌有着特殊的要求。目前国内外制备的银粉大都为球状,为了增加银粉颗问的接触面以提高导电性能,通常需将球状银粉细磨成片状。纤维状的导电材料可以形成网状导电回路,能有效提高导电材料的导电性能。因此,作者综合分析了目前国内外银粉的制备方法,结合本课题组制备超细金属或合金粉体材料的经验,提出了采用配位沉淀-热分解法来制备纤维状银粉的新工艺,并研究了新工艺过程的理论基础。 本文首先根据同时平衡原理和质量守恒原理,推导出了常温下Ag(Ⅰ)-C2O42--NH3-NH4+-H2O体系热力学平衡的数学模型,计算并绘制了该体系的金属离子浓度对数-pH图,确定了配位沉淀法制备前驱体实验研究的pH值范围。在此基础上,实验研究了溶液体系各项物理化学条件对前驱体粒度和形貌的影响,结果表明：两段式添加沉淀剂的反加料方式,反应温度为60℃,Ag+浓度为0.4mol/L,溶液的pH值为3.8～4.8,加料30min,陈化30min,搅拌速率600r/min,PVP的加入量为m(PVP)/m(AgNO3)=0.1时能制备得到棒状前驱体。 本文还根据热分解过程的热力学理论分析了草酸银盐直接热分解得到金属银粉的可行性和银粉的热稳定性。系统研究了前驱体形貌、热分解温度、热分解时间和气氛对热分解产物的影响。结果表明：在VN2：VCO2=3：1的气氛中,热分解温度为140℃,升温0.5h,保温2.5h时可制备得到分散性良好的纤维状银粉,比表面积达1.054m2/g。
[Abstract]:The use of ultrafine powders is closely related to their properties, and their properties depend to a great extent on their morphology and particle size. As a key material in microelectronics industry, silver powder has special requirements for its morphology. At present, the silver powder prepared at home and abroad is mostly spherical. In order to increase the contact surface of silver powder to improve the electrical conductivity, it is usually necessary to fine grind the silver ball powder into flake shape. The fibrous conductive material can form a network conductive circuit, which can effectively improve the conductive properties of conductive materials. Therefore, the author synthetically analyzed the preparation methods of silver powder at home and abroad, combined with the experience of our group in the preparation of ultrafine metal or alloy powder materials, and put forward a new technology of preparing fibrous silver powder by coordination precipitation-thermal decomposition method. The theoretical basis of the new process is also studied. Based on the principle of simultaneous equilibrium and mass conservation, the mathematical model of thermodynamic equilibrium of Ag (鈪，
本文编号：2157007
[Abstract]:The use of ultrafine powders is closely related to their properties, and their properties depend to a great extent on their morphology and particle size. As a key material in microelectronics industry, silver powder has special requirements for its morphology. At present, the silver powder prepared at home and abroad is mostly spherical. In order to increase the contact surface of silver powder to improve the electrical conductivity, it is usually necessary to fine grind the silver ball powder into flake shape. The fibrous conductive material can form a network conductive circuit, which can effectively improve the conductive properties of conductive materials. Therefore, the author synthetically analyzed the preparation methods of silver powder at home and abroad, combined with the experience of our group in the preparation of ultrafine metal or alloy powder materials, and put forward a new technology of preparing fibrous silver powder by coordination precipitation-thermal decomposition method. The theoretical basis of the new process is also studied. Based on the principle of simultaneous equilibrium and mass conservation, the mathematical model of thermodynamic equilibrium of Ag (鈪，
本文编号：2157007
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