毕业设计（论文）-CLNT陶瓷的低温烧结及介电性能的研究精选.doc

CLNT陶瓷的低温烧结及介电性能的研究 摘 要 摩尔比为0.7:0.25:0.35:2的CaO-Li2O-Nd2O3-TiO2（简写为CLNT）陶瓷是一种用于移动通讯介质谐振器的高介电常数微波介质陶瓷。为了实现电子元件和终端系统的小型化，需要CLNT陶瓷与贱金属Ag、Cu实现低温共烧。因此，本文通过在CLNT陶瓷中添加BCB，旨在降低该体系烧结温度，同时保持良好的介电性能，并初步探讨了烧结剂的掺入对体系烧结特性、相组成、微观形貌和介电性能的影响。实验结果发现添加5wt%BCB的CLNT陶瓷的烧结温度降低到950℃。试样在950℃烧结3h，其晶粒生长发育良好，大小均匀，气孔率低。可以认为，BCB促进了CLNT的液相烧结，使其烧结温度降低，阻止了晶粒的异常生长，结果得到致密化组织。结果表明，添加5wt%BCB的CLNT陶瓷具有相对较好的综合介电性能：εr=94，tanδ=0.096，τf =0.6×10-6/℃（1 MHz）。 关键词：微波介质陶瓷，CLNT，低温烧结，BCB，介电性能 LOW-TEMPERATURE FIRING AND MICROWAVE DIELECTRIC PROPERTIES OF CLNT CERAMICS ABSTRACT 0.7:0.25:0.35:2 molar ratio of the CaO-Li2O-Nd2O3-TiO2 (referred as CLNT) ceramics for mobile communications is a high permittivity microwave dielectric ceramics used as dielectric resonator. In order to achieve miniaturization of terminal systems, we need to cofire CLNT ceramics with base metals Ag, Cu at low temperature. Therefore, this article choose BCB as sintering adds and reduce the sintering temperature of CLNT, while maintaining good dielectric properties and preliminary study of the incorporation of sintering additives on the sintering behavior, phase composition, microstructure, dielectric properties were investigated. It is revealed from the experimental results that in CLNT ceramic, with the addition of 5wt% BCB and sintered at 950℃ for 3h, the grains grow well, the sizes of the grains are nearly the same, and the porosity obviously lowers. We can conclude that it is the addition of BCB that prompted the process liquid phase sintering, which made the sintering temperature of CLNT ceramics lower, prevented the abnormal growth, and consequently obtained compacted feature Thus, It has comparatively satisfying comprehensive dielectric properties, εr=94, tanδ=0.096, τf =0.6×10-6/oC (1 MHz). KEY WORDS: microwave dielectric ceramics, CLNT, low temperature sintering, BCB, dielectric properties 符号说明 r 介电常数 介电损耗 频率温度系数 Q×f 品质因数 SEM Scanning Electron Microscope 扫描电子显微镜 XRD X ray diffraction X-射线衍射仪 目 录 第一章 绪 论 1 §1.1 微