毕业设计（论文）-添加BCB和NCB的CLST微波介质陶瓷的显微结构精选.doc

添加BCB和NCB的CLST微波介质陶瓷的 显微结构 摘 要 CaO-Li2O-Sm2O3-TiO2（CLST）具有正交钙钛矿结构，由于具有优异的微波介电性能而受到了广泛的关注。当CaO、Li2O、Sm2O3和TiO2的摩尔比为16：9：12：63时，CLST陶瓷具有较好的介电性能。但是其烧结温度在1300℃以上，远远不能满足低温共烧。通过在CLST陶瓷中加入助烧剂可以降低其烧成温度，然而对于微波介质陶瓷的研究，，BaCu(B2O5)（BCB）（850）Na2O-CaO-B2O3（）CLST陶瓷中添加4wt%BCB和1wt%NCB，降低该体系烧结温度，借助于扫描电子显微镜(SEM)和透射电子显微镜(TEM)分析试样的晶体和玻璃等相的形貌、分布等，初步探讨了BCB与NCB的掺入对该体系的显微结构、介电性能的影响及三者之间的关系。实验结果发现添加4wt%BCB和1wt%NCB的CLST陶瓷的烧结温度降低到1050℃。试样在1050℃烧结3h，其晶粒生长发育良好，大小均匀，气孔率较低。可以认为，BCB和NCB促进了CLST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。实验结果表明，添加4wt%BCB和1wt%NCB的CLST陶瓷具有相对较好的综合介电性能：εr =81，tanδ=0.021，=0.5 ×10-6/℃（1 MHz）。 关键词：微波介质陶瓷，介电性能，显微结构， SEM，TEM Microstructure of CLST Microwave Dielectric Ceramics With Addition of BCB And NCB ABSTRACT CaO-Li2O-Sm2O3-TiO2（CLSTceramics which are of orthorhombic perovskite structure,have been widely studied for their excellent microwave dielectric properties.It was reported that CLST ceramic would exhibit good dielectric properties,when the mole ration of CaO、Li2O、Sm2O3 and TiO2 is 16:9:12:63.However,the sintering temperature above 1300℃ ,which is far from the LTCC. the people always focus on the component materials in microwave dielectric ceramics research, so as to neglect?the material microstructure on the properties. BaCu (B2O5) (BCB) has a low melting point (850℃) and Na2O-CaO-B2O3 (NCB) of the melting point is 800℃.Hence, we add 4wt% BCB and 1wt% NCB in CLST(mole ration,16:9:12:63) to lower its sintering temperature and to analyze the features and distributions etc. of grains,with the aids of Scanning Electron Microscope(SEM) and Transmission Electron Microscopy (TEM).And the influence of the addition of BCB and NCB in CLST and the link between microstructure and dielectric properties are primitively studied.It is revealed from the experimental results that in CLST ceramic,with the addition of 4wt% BCB and 1wt% NCB and sintered at 1050℃for 3h, the grains grow well,the sizes of the grains are nearly the same,and the porosity obviously lowers.We can conclude that i