發(fā)布時間：2018-03-22 03:00

  本文選題：多層陶瓷電容器　切入點：掃描電子顯微鏡　出處：《電子科技大學》2014年碩士論文　論文類型：學位論文

【摘要】：多層陶瓷電容器是軍用電子設備中重要的電子元件。隨著軍用電子設備要求不斷提高,工作環(huán)境越來越苛刻,保證多層陶瓷電容可靠性成為了一個亟待解決的問題。本文利用現(xiàn)代微觀分析手段(主要包括掃描電子顯微鏡和X射線能譜儀)對多層陶瓷電容器相關質量問題進行了研究和總結,并利用計算機編程語言開發(fā)多層陶瓷電容器數(shù)據(jù)庫軟件。利用掃描電子顯微鏡的二次電子成像方式對瓷粉和燒結后的陶瓷介質進行分析,背散射電子像成像方式對端電極錫鉛層進行觀察。使用X射線能譜儀的線掃描和面掃描模式對鍍層和介質擊穿失效位置的分析。通過以上分析所得到的相關信息都有助于提高產(chǎn)品的質量。對多層陶瓷電容器端電極質量相關問題進行了分析,主要涉及了端電極污染、焊接失效和電鍍工藝。經(jīng)過微觀分析和進一步的討論可知:端電極的污染物是在端燒結過程中,殘留在燒成板和燒結爐中的鈦鍶鉍系介質材料引入的;焊接失效和鍍層脫落樣品的端電極中玻璃相溢出明顯,導致后期電鍍異常,最終表現(xiàn)為脫端現(xiàn)象;在電鍍錫工藝中,錫結晶情況隨電鍍位置變化,最終找到了合適的電鍍位置。針對多層陶瓷電容器內電極分叉現(xiàn)象,對問題樣品的內電極、陶瓷介質和端電極銀漿料進行了微觀分析。深入討論了引起分叉現(xiàn)象的原因和機理。內電極分叉現(xiàn)象并不是發(fā)生在鑲樣制備和生坯切割過程,而是發(fā)生在銀漿燒結過程中。1187型銀漿在800℃和850℃下燒結均出現(xiàn)分叉現(xiàn)象,而p212型銀漿在不同燒結溫度下均未出現(xiàn)分叉現(xiàn)象且與內電極結合良好。1187型銀漿與陶瓷介質匹配性不佳,且該試樣內電極與陶瓷介質間殘余應力較大,使得銀漿中的玻璃相容易滲入陶瓷介質形成分叉。在長期的多層陶瓷電容器微觀分析工作中,積累了大量的分析案例。為了更加有效地管理這些分析案例,利用面向對象語言C++和結構化查詢語言SQL,結合使用微軟基礎類庫MFC,在VC6.0和SQL Server 2005環(huán)境下開發(fā)實現(xiàn)了多層陶瓷電容器數(shù)據(jù)庫軟件。該數(shù)據(jù)庫軟件實現(xiàn)了對所有分析案例的閱讀、查詢、添加、刪除和修改。通過以上工作,對多層陶瓷電容器端電極相關質量問題進行了深入地分析,切實解決了生產(chǎn)工藝中存在的問題;對內電極分叉現(xiàn)象進行了詳細的討論,找到了其產(chǎn)生機理;利用相關編程軟件和數(shù)據(jù)庫,實現(xiàn)了多層陶瓷電容器數(shù)據(jù)庫軟件,該軟件收錄了大量案例,具有很高的參考價值。
[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，

本文編號：1646733