De-sintering of Ba₅Nb₄O₁₅ ceramic and its influence on microwave characteristics

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• 作者：Chung-Ya Tsao^a ; Wei-Hsing Tuan^a ; ^{tuan@ntu.edu.tw} ; Kuei-Chih Feng^b
• 关键词：Microwave ; Sintering ; Ba5Nb4O15 ; Grain growth ; Crystal structure
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：37
• 期：4
• 页码：1517-1521
• 全文大小：1705 K
• 卷排序：37

文摘

The sintering behaviour of a cation-deficient perovskite, Ba5Nb4O15, is investigated in the present study. The highest density can be achieved through pressureless sintering at 1250 °C is only 93%. A further increase in sintering temperature results in a decrease in density; for example, the density is only 82% after sintering at 1435 °C. The density decrease, de-sintering, can be related to the formation of abnormal grains ( > 1250 °C) and the reduction of niobium ions ( > 1400 °C). The permittivity of sintered Ba5Nb4O15 specimen shows strong dependence on density; however, the quality factor (Qxf) increases to 45,000 with the increase of sintering temperature. The increase in quality factor is attributed to the ordering of cations in the perovskite structure.