Preparation And Properties Of Barium Titanate Powders By Microwave Micro Region Solid State Sintering Method

Barium titanate（Ba Ti O₃）,as an ABO₃ type perovskite compound,which widely used in various passive electronic components due to its excellent physical and chemical properties.With the development of miniaturization,thin media and high performance of electronic components,barium titanate powders are required to have small particle size,uniform size,and high tetragonal content.Due to the hydroxyl defects in the cubic Ba Ti O₃ prepared by the liquid phase method,pores will appear during sintering of MLCC,which will affect the performance.Therefore,improving the traditional solid state method to prepare high-performance barium titanate powder is the direction of the industry’s efforts.For example,Japan’s Taiyo Yuden has prepared tetragonal barium titanate with an average particle diameter of 150 nm through solid-state synthesis.However,the related technology is strictly confidential in China,resulting in more than 80%of Ba Ti O₃ powders with a particle size of 200 nm and below relying on imports.There is a serious risk of"stuck neck".In this paper,Ba CO₃ and Ti O₂are used as raw materials,Glycine and Alanine are used as sintering aids,and Si C and other microwave conductors are added to form microwave micro-areas and uniformly heated to prepare high-performance Ba Ti O₃ nanopowders.Using XRD,SEM,FTIR,Raman and other methods to characterize Ba Ti O₃,studied the separate sand milling process,burn aid concentration,microwave good conductor addition,calcination method,reaction temperature and holding time to Ba Ti O₃ powder morphology,crystal equal The impact of physical and chemical properties has achieved the following research results:（1）Separate sand milling is used to disperse Ba CO₃ and rutile Ti O₂,which solves the situation of heterogeneous nucleation due to high-speed collision of raw materials during mixed sanding.The effects of different dispersion methods and sand milling time on the morphology and crystal phase of Ba Ti O₃were studied.The results show that the separate sand milling can effectively shorten the raw material dispersion time,avoiding the generation of Ba Ti O₃crystal nucleus and mesophase Ba₂Ti O₄.The optimal sanding time for Ba CO₃ and rutile Ti O₂ is 90 min and 45 min.（2）Glycine-assisted microwave solid-state synthesis of Ba Ti O₃ overcomes the problems of high temperature and long heating time in traditional solid-state synthesis.The effects of glycine action mechanism,synthesis temperature and holding time on the morphology and crystal phase of Ba Ti O₃ powder were analyzed.The results show that glycine shifts the Ba3d electron energy in Ba CO₃ by 0.5 e V,reduces the decomposition temperature of Ba CO₃,and promotes the formation of Ba Ti O₃.The precursor is kept in a microwave sintering furnace at 700℃for 1 hour and 900℃for 1 hour to prepare Ba Ti O₃powder with high tetragonal phase content and uniform particle size distribution.（3）The tetragonal Ba Ti O₃ was prepared by alanine assisted microwave micro-domain solid phase.The introduction of Si C as a good microwave conductor solves the problem of poor microwave absorption of raw materials and the microwave heating lag.The effects of the action mechanism of alanine,the amount of Si C added,the reaction temperature and the holding time on Ba Ti O₃ were investigated.XPS results show that alanine can replace glycine as a burning aid and reduce the decomposition temperature of Ba CO₃.And as the amount of Si C added increases,the synthesis temperature of Ba Ti O₃ decreases accordingly.When the amount of Si C added is 20 wt%,the Ba Ti O₃ powder obtained at 850℃has the best performance.