新型CLT-LMT陶瓷微波烧结机理及介电损耗机制研究

In this project, microwave sintering processes are used for preparing the new Ca0.61Ln0.26TiO3-LnMg0.5Ti0.5O3 (Ln=La,Nd,Sm; CLT-LMT) ceramics to reduce sintering temperature and shorten sintering time; densification and grain growth behavior of CLT-LMT are observed to build microwave sintering kinetic equation and explore the microwave sintering mechanism; the effects of composition and preparation processes on sintering properties, microstructures, phases and microwave dielectric properties of CLT-LMT ceramics are studied systematacially; the crystal structure parameters are detected by Rietvesd method and TEM analysis, meanwhile, chemical bond parameters and valency of cations in CLT-LMT ceramics are analysed by XPS; the relationships linking from dielectric properties such as dielectric constant, dielectric loss and temperature coefficient of resonant frequency to the crystal structures and chemical bond parameters are discussed to reveal the mechanism of dielectric loss and dielectric polarization; the CLT-LMT ceramics with exellent microwave dielectric properties are obtained. This project aims to provide basic data and theoretical basis for the possible applications of CLT-LMT ceramics to mobile communication and satellite communication. Most importantly, the research of this project is expected to promote the development of microwave sintering theory of microwave dielectric ceramics, the fullest use and the increase in the additional value of the abundant rare earth resources of Jiangxi province.

本项目拟采用微波烧结工艺制备Ca0.61Ln0.26TiO3-LnMg0.5Ti0.5O3(Ln=La,Nd,Sm; CLT-LMT)新材料体系以降低其烧结温度、缩短其烧结时间，研究CLT-LMT陶瓷的致密化过程及晶粒生长行为，与常规烧结对比，建立微波烧结动力学方程，阐明其微波烧结机理。同时系统研究成分配比、制备工艺对烧结性能、物相组成、显微结构及微波介电性能的影响；采用XRD全谱拟合方法、透射电子显微分析测定其晶体结构参数，采用XPS分析其化学键参数和阳离子价态，探讨介电常数、介电损耗和谐振频率温度系数与晶体结构之间的关系，结合键价理论揭示其介电极化及介电损耗机制，制备微波介电性能优异的CLT-LMT陶瓷。本项目的研究将为CLT-LMT陶瓷在移动通讯、卫星通讯领域的可能应用提供基础数据和理论依据,促进微波介质陶瓷微波烧结理论的发展，有利于充分利用江西省丰富的稀土资源并提升其附加值。

采用微波烧结工艺制备Ca0.61Ln0.26TiO3-LnMg0.5Ti0.5O3(Ln=La,Nd,Sm; CLT-LMT)新材料体系，降低其烧结温度、缩短其烧结时间，研究了CLT-LMT陶瓷的致密化过程及晶粒生长行为，建立了0.65CLT-0.35SMT陶瓷的晶粒生长动力学模型。同时系统研究了成分配比、制备工艺对烧结性能、物相组成、显微结构及微波介电性能的影响；采用XRD全谱拟合方法测定其晶体结构参数，探讨介电常数、介电损耗和谐振频率温度系数与晶体结构之间的关系，结合键价理论阐明了其介电极化及介电损耗机制，制备了微波介电性能优异的CLT-LMT陶瓷。本项目的实施为CLT-LMT陶瓷在5G移动通讯、卫星通讯领域的应用提供了基础数据和理论依据，有利于促进微波介质陶瓷微波烧结理论的发展，有利于充分利用江西省丰富的稀土资源并提升其附加值。