Mg2SiO4纳米晶陶瓷及其纳米复合微波介质的制备、介电性能调控

For the development of microwave devices with LTCC technology，this project aims at developing the nancomposite microwave dielectrics based on Mg2SiO4(MS) compounds. We will use a Sol-Gel technology to form core-shell type MS/CaTiO3 nanocomposites and a high-energy ball milling method for o/o type nanocomposites. For the fabrication of microwave dielectric ceramics with nano-size grains, the two step sintering process will be employed. We will investigate effects of grain size on the microwave dielectric properties of MS microwave dielectric ceramics; also, we will study the microstructures of 0/0 and core-shell type nanocomposites and establish the relationship among microstructures and dielectric properties of the studied systems. Various sintering agents will be used to low the sintering temperatures of ceramics for the development of LTCC nanocomposite dielectrics. Thus, this project is important for scientific and technical development.

本项目针对LTCC技术及多层微波元器件对纳米微波介质复合材料的应用需求，以Mg2SiO4(MS)为基础，采用高能球磨和Sol-gel工艺制备MS/CaTiO3的0/0型以及核壳结构纳米复合微波介质材料，两步烧结或热压烧结获得MS纳米晶陶瓷。研究晶粒尺寸对MS纳米陶瓷微波介电性能的影响，探讨晶粒尺寸效应机理；研究纳米复合材料的微波介电响应行为及界面结构对其微波介电性能的影响；研究不同烧结助剂对复合材料的降温效果，获得一至两种低温烧结和高性能兼优的LTCC纳米复合微波介质材料。因此，本项目具有重要的学术价值和实际应用价值。

本项目针对LTCC技术及多层微波元器件的应用需求，采用高能球磨、水热法分别获得了平均晶粒尺寸147/60 nm的Mg2SiO4粉体，两步烧结工艺制备了微/纳米晶陶瓷，研究了晶粒尺寸引起微波介电性能的变化规律；固相反应法制备了一系列A位Ca、Cu置换Mg，B位V置换Si的有限固溶体，研究了结构、显微组织和微波介电性能的关系；引入LiF为烧结助剂，在低温液相和晶格活化的共同作用下将Mg2SiO4陶瓷烧结温度从1450°C降低到950°C而不降低Q×f值；制备了一系列Mg2SiO4/TiO2、Mg2SiO4/Ca0.9Sr0.1TiO3、Mg2Si0.9V0.1O4/Ca0.8Sr0.2TiO3、Mg1.9Cu0.1SiO4/(La0.5Na0.5)TiO3微/纳米复相陶瓷，在烧结助剂和纳米活化的作用下900 °C获得了致密陶瓷，并将其τf 值调控到了近零值，获得了一系列性能优异的LTCC材料。本项目还拓展了研究内容，开发了SiO2、Ca5A4(VO4)6 (A2+= Mg, Zn)、Li2Mg3BO6 (B = Ti, Sn, Zr)、LiAlW2O8、(Mg0.95Zn0.05)2(Ti0.8Sn0.2)O4、AWO4 (A = Ca, Ba, Sr)等新型低温烧结、低介电常数高Q值的微波介质材料。本项目发表SCI论文28篇，申报国家发明专利8项(已授权6项)。