“正方形”MLCC产品的DPA与无损检测

对多层瓷介电容器(MLCC)产品进行超声波无损检测时,要求使MLCC的内电极平行于水平面放置。而对于那些无法知道内电极排列方向的"正方形"产品,就很容易漏检。而且,这类产品在做DPA检测时,无法正确地码放也成了一个问题--既浪费了样品又浪费了时间。因此,对于这类的MLCC产品,能够正确地辨认内电极排列的方向就显得至关重要。通过对MLCC进行超声波扫描与DPA的对比试验,找到了正确辨认内电极排列的方法,由此可以大大提高工作效率。     

多层陶瓷电容器电极用超细铜粉的化学制备工艺研究

以CuSO4溶液为原料,采用NaOH沉淀-葡萄糖预还原-水合肼还原工艺(简称两步液相还原法)制得了粒度均匀可控、分散性好、适用于多层陶瓷电容器(MLCC)电极的球形超细铜粉.试验研究了葡萄糖预还原、水合肼的添加方式以及添加剂聚乙烯吡咯烷酮(PVP)和NH4Cl对超细铜粉粒度和形貌的影响.结果表明:葡萄糖预还原和水合肼的分步添加均有利于超细铜粒子的均匀生长;适量PVP的加入有助于超细铜粉粒径均匀并使其形貌趋于一致;NH4Cl可使铜粉的粒径变小,当Cu与NH4Cl的摩尔比为1∶1时,铜粉的形貌会由类球形向正多面体转变.     

Effect of Cr additions on the microstructural stability of Ni electrodes in ultra-thin BaTiO3 multilayer capacitors

Microstructural control in thin-layer multilayer ceramic capacitors (MLCC) is one of the present day challenges to maintain an increase in capacitive volumetric efficiency. This present paper opens a series of investigations aimed to engineer the stability of ultra-thin Ni electrodes in BaTiO₃-based multilayer capacitors using refractory metal additions to Ni. Here, pure Ni and Ni–1 wt.% Cr alloy powders are used to produce 0805-type BME MLCCs with 300 active layers and with dielectric and electrode layer thickness around 1 μm. To investigate the continuity of Ni electrodes, both MLCC chips with pure and doped electrodes were sintered at different temperatures for 5 h. It is found that the continuity of Ni electrodes is improved most likely due to the effect of Cr on the low-melting point (Ni,Ba,Ti) interfacial alloy layer formation. The interfacial alloy layer is not observed when Cr is segregated at Ni-BaTiO₃ interface in the Cr-doped samples, while it is found in all undoped samples. The interfacial alloy layer is believed to increase mass-transfer along the Ni-BaTiO₃ interfaces facilitating an acceleration of Ni electrodes discontinuities.     

多层陶瓷电容器银电极电镀锡铅失效原因分析

针对多层陶瓷电容器在电镀过程电镀锡铅效果差的问题,利用扫描电子显微镜和能谱仪分析了正常和变差样品银层的微观结构,其结果表明:电镀效果差的样品端电极银层表面出现较大面积的缺损,部分内部介质裸露,影响了后期电镀时银层的导电性,导致电镀效果变差.找出变差的原因.     

高比容MLCC关键制作技术研究

高比容多层陶瓷电容器MLCC关键制作技术包括亚纳米陶瓷材料分散、薄介质用陶瓷浆料流延、内电极金属浆料丝网印刷、高精度叠层及高温烧结精准的气氛控制技术.通过试验研究发现:亚纳米陶瓷粉体使用PVB体系不同聚合度黏合剂采用砂磨方式进行分散,得到的陶瓷浆料分散均匀稳定.采用R2高精度设备PET载带流延方式可制成1μm左右的陶瓷...     

超细镍粉在液相中的分散行为研究

通过测定润湿性、Zeta电位及沉降曲线,研究了溶液pH值、分散介质及表面修饰等对粒径≤2μm的超细镍粉在液相中的分散行为的影响。结果表明,当pH=4时,粉末在水中具有较好的润湿性;经过三乙醇胺（ETA）表面修饰处理后,粉末在无水乙醇中具有优良的分散稳定性;经过离心分级的样品,粒度分布和SEM分析结果表明,采用该方法,分级得到的粉末粒径小、分布均匀,满足高端多层陶瓷电容器产品的要求。