多层陶瓷电容器可靠性的电子显微研究及数据库

发布时间：2018-03-22 03:00

  本文选题：多层陶瓷电容器　切入点：扫描电子显微镜　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：多层陶瓷电容器是军用电子设备中重要的电子元件。随着军用电子设备要求不断提高,工作环境越来越苛刻,保证多层陶瓷电容可靠性成为了一个亟待解决的问题。本文利用现代微观分析手段(主要包括扫描电子显微镜和X射线能谱仪)对多层陶瓷电容器相关质量问题进行了研究和总结,并利用计算机编程语言开发多层陶瓷电容器数据库软件。利用扫描电子显微镜的二次电子成像方式对瓷粉和烧结后的陶瓷介质进行分析,背散射电子像成像方式对端电极锡铅层进行观察。使用X射线能谱仪的线扫描和面扫描模式对镀层和介质击穿失效位置的分析。通过以上分析所得到的相关信息都有助于提高产品的质量。对多层陶瓷电容器端电极质量相关问题进行了分析,主要涉及了端电极污染、焊接失效和电镀工艺。经过微观分析和进一步的讨论可知:端电极的污染物是在端烧结过程中,残留在烧成板和烧结炉中的钛锶铋系介质材料引入的;焊接失效和镀层脱落样品的端电极中玻璃相溢出明显,导致后期电镀异常,最终表现为脱端现象;在电镀锡工艺中,锡结晶情况随电镀位置变化,最终找到了合适的电镀位置。针对多层陶瓷电容器内电极分叉现象,对问题样品的内电极、陶瓷介质和端电极银浆料进行了微观分析。深入讨论了引起分叉现象的原因和机理。内电极分叉现象并不是发生在镶样制备和生坯切割过程,而是发生在银浆烧结过程中。1187型银浆在800℃和850℃下烧结均出现分叉现象,而p212型银浆在不同烧结温度下均未出现分叉现象且与内电极结合良好。1187型银浆与陶瓷介质匹配性不佳,且该试样内电极与陶瓷介质间残余应力较大,使得银浆中的玻璃相容易渗入陶瓷介质形成分叉。在长期的多层陶瓷电容器微观分析工作中,积累了大量的分析案例。为了更加有效地管理这些分析案例,利用面向对象语言C++和结构化查询语言SQL,结合使用微软基础类库MFC,在VC6.0和SQL Server 2005环境下开发实现了多层陶瓷电容器数据库软件。该数据库软件实现了对所有分析案例的阅读、查询、添加、删除和修改。通过以上工作,对多层陶瓷电容器端电极相关质量问题进行了深入地分析,切实解决了生产工艺中存在的问题;对内电极分叉现象进行了详细的讨论,找到了其产生机理;利用相关编程软件和数据库,实现了多层陶瓷电容器数据库软件,该软件收录了大量案例,具有很高的参考价值。
[Abstract]:Multilayer ceramic capacitors are important electronic components in military electronic equipment. It is an urgent problem to ensure the reliability of multilayer ceramic capacitors. This paper deals with the quality problems of multilayer ceramic capacitors by means of modern microanalysis (including scanning electron microscope and X-ray energy spectrometer). Has carried on the research and the summary, The database software of multilayer ceramic capacitor is developed by using computer programming language. The ceramic powder and ceramic medium after sintering are analyzed by using the secondary electron imaging method of scanning electron microscope. Observation of tin and lead layers at end electrode by backscatter electron imaging. Analysis of failure locations of coatings and dielectric breakdown by using line and surface scanning modes of X-ray energy spectrometer. Relevant information obtained from the above analysis. The problems related to the quality of the electrode at the end of the multilayer ceramic capacitor are analyzed. The pollution of end electrode, welding failure and electroplating process are mainly involved. Through microcosmic analysis and further discussion, it can be seen that the contamination of end electrode is introduced in the process of end sintering, which remains in the sintering plate and sintering furnace of titanium-strontium bismuth series dielectric material; The glass-phase overflow in the end electrode of the welding failure and the exfoliation of the coating resulted in the late electroplating anomaly, which eventually appeared as the phenomenon of de-termination, and the crystallization of tin changed with the electroplating position in the electroplating process. Finally, a suitable electroplating position was found. In view of the phenomenon of internal electrode bifurcation in multi-layer ceramic capacitors, the internal electrode of the problem sample was studied. The microcosmic analysis of silver paste with ceramic dielectric and end electrode was carried out. The causes and mechanism of the bifurcation were discussed in depth. The phenomenon of internal electrode bifurcation did not occur in the process of sample preparation and blank cutting. Instead, during the sintering process of the silver paste, the. 1187 type silver paste sintered at 800 鈩，

本文编号：1646733