【作者】 袁颖；

【导师】 赵康； 井晓天；

【作者基本信息】 西安理工大学 ， 材料学， 2006， 硕士

【摘要】 片式多层陶瓷电容器(MLCC)是表面组装技术中应用最广泛的元件,电极浆料是MLCC关键和基础的材料,电极浆料的性能对MLCC的发展起着举足轻重的作用。目前,MLCC基本使用贵金属Ag和Ag-Pd浆料,而Ag浆料、Ag-Pd浆料在某些条件下还存在一些不足,如Ag浆料制得的电极耐焊性差和银在高湿强电场作用下的迁移率高等;另外,Ag-Pd浆料的电阻率较高、价格昂贵。为了适应快速发展的微电子技术,国内外都在寻求性能优良、价格低廉的贱金属材料作为电子浆料的导电相。用贱金属Ni、Cu代替贵金属,成为国内外研究的热点。目前,铜粉用于电子浆料领域研究的重点是提高其抗氧化性,使其能在大气气氛下烧结,以降低元件成本。对铜粉进行表面处理是防止铜粉氧化最主要的方法。本实验通过用滴入化学反应法在铜粉表面包覆一层银,来提高铜粉的抗氧化性。通过正交实验,对样品进行微观形貌观察,XRD图谱分析,粒度测试以及TG分析,得出以下结论:制备银包覆铜粉的最佳工艺参数为:Ag、Cu摩尔比为0.8;银氨浓度0.12mol/L;明胶浓度20g/L;滴速10滴/分钟,反应温度50℃。其中Ag、Cu摩尔比对包覆粉的包覆效果起着决定性作用。采用滴入化学法制备银包覆铜粉,可控性高,包覆层致密、均匀。实验制备的银包覆铜粉,其大气下抗氧化温度在800℃以上,能够满足大气下高温烧结的要求。用上述包覆粉制备了银铜电极浆料,讨论了金属粉形状、玻璃粉含量、烧结温度和保温时间对电极性能的影响,得出结论如下:电极浆料中金属粉采用球状银包覆铜粉,金属粉与玻璃粉的混合粉占浆料的80%,其中玻璃粉占混合粉的6%,有机载体占浆料的20%。电极烧结工艺为:烧结温度为800℃,保温时间为10min。经过测试,银铜粉电极有良好的导电性,附着力能够达到元件使用要求,耐焊性优于银电极,可焊性与银电极相当。更多还原

【Abstract】 Multi-layer ceramic capacitor (MLCC) is the most important chip component in the surface mount technology, and electrode paste is the key and foundation materials for MLCC, electrode paste capability of MLCC played a dominant role in the development of it. Currently, MLCC used precious metals Ag and Ag-Pd as the function phase of the electrode paste. But Ag and Ag-Pd electrode paste have some defects, such as paste of silver system of electrode bear the soldering bad and the silver is under the high and wet strong electric field action of migration etc, the resistivity of the Ag- Pd paste is higher, the price is expensive. For adapting the development of micro-electronics technique, people begin searching for the cheap base metals material as conduct phase of the electronic paste. The copper powder because of its lower resistivity, has become the main substitute of the precious metal paste. Recently, the main research of the copper powder is raising the antioxidation temperature of it.We use the method of chemistry substitution reaction coating silver in the copper powder surface in order to improve the temperature of oxidation resistance. The surface topography, microstructure and oxidation resistance of the coated powder were characterized by SEM, XRD, TG and other methods. We get the results as following:The ratio of Ag and Cu is 0.8; the solution concentration of silver ammonia is 0.12mol/L; the gelatin concentration is 20g/L; the dropping velocity is 10 drop/min and the reaction temperature is 50℃. the coating effect is largely responsible for ratio of Ag and Cu, The process of coating powder adopted drop chemical method, have better controllability, and coating is compact. The silver coated copper powder we prepared had higher antioxidation temperature, and can sintering at the oxidized atmosphere.With silver coated copper powder, we fabricated electrodes paste, and analysed the adhesion force, square resistance, get a conclusion as follows: Taking the globosity copper powder as the function phase, the content of the glass phase is 6%, sintering at the temperature of 800℃and maintaining 10mins, we can get the excellent electrode film.更多还原