De-sintering of Ba5Nb4O15 ceramic and its influence on microwave characteristics
Journal
Journal of the European Ceramic Society
Journal Volume
37
Journal Issue
4
Pages
1517-1521
Date Issued
2017
Author(s)
Abstract
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.
Type
journal article