摘要
采用改进的机械化学作用与混杂工艺相结合的制备方法,在1200℃制备出结晶完全、致密的细晶(Ba0.75Sr0.25)Ti03-MgO(BST-MgO)复合陶瓷材料,其烧结温度比传统的固相反应低150-300℃。样品的介电性能研究发现,介电温谱在一50℃左右,介电常数呈明显的弥散现象,这是由于复合块体材料细晶的微观结构与非铁电相MgO共同作用的结果。样品的居里点在5℃左右,在居里点介电常数呈现介电弛豫现象。在室温、100kHz时,介电常数和介电损耗分别约为1300和0.005;在偏置电场为1.0kV/mm时,介电可调性为S%o。
A well-developed, dense and fine-grained (Ba0. 75 Sr0. 25 ) TiOa-MgO (denoted as BST-MgO) ceramic composite was fabricated at low sintering temperature of 1200 ℃ using a modified hybrid processing based on the mechanochemical technique. The fabrication temperature was 150--300 ℃ lower than that required by using conventional solid-state process. Temperature dependent didectric constant and loss tangent of the BST-MgO composite exhibited two phase transitions. The first one was at about --50 ℃, showing a broad and diffused phase transition; while the second one was at about 5 ℃ (the expected Curie temperature), indicating a relaxation phenomenon. At 100 kHz and room temperature, the measured dielectric constant and low loss tangent were about 1300 and 0. 005, respectively. Finally, the measured dielectric room-temperature tunability at 100 kHz and 1 kV/mm were found to be 5 %.
基金
江苏省自然科学基金(BK20131153)
江苏高校优势学科建设工程资助项目
苏州科技学院氧化物薄膜材料与光学信息协同创新中心
关键词
混杂工艺
机械化学
烧结
细晶
可调度
hybrid processing, mechanoehemical, sintering, fine-grained, tunability