摻雜稀土元素之Z5U-BME陶瓷電容器的製備和特性研究

Abstract

本論文之內容,在於研發BME-Z5U鈦酸鋇陶瓷電容器,並以各種不同電性,物 性之量測,了解實驗結果是否達到計劃所須要之目標,再針對實驗結果不足 的地方,通盤檢討實驗流程,以求符合計劃所規定之電性和物性的條件。在 實驗製程中,我們以在還原氣氛鎳電極共燒的方法製備BME-Z5U陶瓷電容器 以取代傳統昂貴鈀，銀電極一般氣氛燒結的方式,並且經過適當的退火程 序以得到高介電常數,低損耗,高絕緣電阻之電容器。在電性研究上,稀土 元素(Dy,Ho)之摻雜有助於介電常數的提高,居里溫度點隨著Dy2O3摻雜量 之提升而些微下降。另外發現鎳電極共燒的方式,其介電常數有明顯下降 的趨勢。我們推測原因乃是在燒結時,鎳元素擴散進入主體。對於塗銅電 極的試片,由於再經過一次熱處理而使得居里溫度和鎳共燒及塗In-Ga alloy 的試片有顯著之差異。 The Z5U Ni electrode ceramic capacitors with the main composition of (Ba,Ca)(Ti,Zr)O3 system were studied. Since the capacitor with Ni electrode should be fired in a reducing atmosphere to prevent the oxidation of Ni, thay have a problem in that the electrical properties is far worse than that of the capacitors with Pd electrode due to the formation of oxygen vacancies in the ceramic bodies of capacitors. The influence of rare-earth additives, such as Dy and Ho on the electrical properties and microstructure of (Ba,Ca)(Ti,Zr)O3 composition capacitor was investigated. Addition of Dy2O3 has little effect in the shift of Curie point and the increasing of k value,but the effect of grain growth inhibition was not found. The Curie peak of the samples co-fired with Ni electrode is more depressed than the samples without co-fired with Ni which are painted with In-Ga alloy. We assume this difference was probably caused by diffusion of Ni into the dielectrics during co-firing with Ni electrode. On the other hand, Curie point of the samples painted with Cu electrode is different than the samples co-fired with Ni electrode or painted with In-Ga alloy.