改性(Sr,Ca)TiO3基储能陶瓷介电及MLCC性能研究

工业级脉冲储能多层瓷介电容器(MLCC)是现阶段国内研制和生产电子启动装置的重要元器件, 针对国内主要有机薄膜电容器尺寸大、寿命短、可靠性较低的不足, 本研究采用传统固相反应法, 制备了SrTiO₃和CaTiO₃基的脉冲储能介质陶瓷材料, 研究了微量助烧剂掺杂, 以及Sr²⁺/Ca²⁺相互掺杂对陶瓷材料的介电性能的影响, 并进一步制备和研究了以(Sr,Ca)TiO₃为基体MLCC性能。实验结果表明: 通过加入质量分数1.0%的助烧剂, 引入微量Bi³⁺ 可取代Sr²⁺, 提高了SrTiO₃材料的介电常数, 而Bi³⁺对CaTiO₃基材料的介电性能无明显影响; Mn元素有效抑制高温烧结中Ti⁴⁺的还原, 降低介电损耗; 加入助烧剂有效降低瓷粉的烧结温度, 提高材料的致密性。(Sr_xCa_1-x)TiO₃体系的MLCC可保持较高的介电常数和较低的介电损耗, 当 x=0.4 时, 其介电损耗tanδ=1.8×10^-4, 击穿强度为59.38 V/μm, 高低温放电电流变化率为±7%, 放电稳定, 在常温和高温(125 ℃)下经1000次循环充放电实验均未失效, 是一种在不同电场强度下具有相对较优的容量稳定性以及较高可靠性的脉冲特性(Sr,Ca)TiO₃基电容器陶瓷介质材料。

Dielectric and MLCC Property of Modified (Sr,Ca)TiO3 Based Energy Storage Ceramic

Industrial pulse energy storage multilayer ceramic capacitors (MLCC) are important components for the development and production of electronic starting devices in China. In view of the shortcomings of large size, short life and low reliability of organic film capacitors, SrTiO₃ and CaTiO₃ based pulse energy storage dielectric ceramics were prepared by traditional solid-state reaction method in this study. The effects of sintering aid doping and Sr²⁺/Ca²⁺ mutual doping on the dielectric properties of ceramic materials were studied, and the property of MLCC based on (Sr,Ca)TiO₃ were further prepared and investigated. The results show that the dielectric constant of SrTiO₃ materials can be improved by adding the sintering aid with a mass ratio of 1.0%, such as the introduction of trace Bi³⁺, while Bi³⁺ has no obvious effect on the CaTiO₃ based materials. Doping of Mn element can effectively inhibit the reduction of Ti⁴⁺ during high-temperature sintering and reduce dielectric loss. Moreover, the addition of sintering aid can effectively reduce the sintering temperature of ceramic powder and improve the compactness of the material. The MLCC prepared from (Sr_xCa_1-x)TiO₃ material can maintain high dielectric constant and low dielectric loss, at x=0.4, the dielectric loss tanδ=1.8×10^-4, the breakdown strength is 59.38 V/μm, and the high and low temperature discharge current change rate is ±7%, which shows good discharge stability. In addition, no matter it is at room temperature or high temperature (125 ℃), the sample has no failure after 1000 cycles of discharge experiment. Therefore, the as-obtained (Sr, Ca)TiO₃ based ceramic dielectric material can be a promising pulse capacitor with relatively excellent capacity stability and high reliability under different electric field strength.