Doping And Surface Modification Of Barium Titanate

As the primary material for high dielectric constant ceramic capacitor,bariumtitanate （BaTiO₃）, withaperovskitestructure（ABO₃）, has excellent electronicperformancesuchas ferroelectric, piezoelectric, positive temperature coefficient effectandhighdielectric constant, etc. And as a kind of important electronic components,ceramic capacitors are widely used in very field such as military field and automotivefiled.High dielectric constant ceramic capacitor could be used as a storage battery.This kind of ceramic capacitors have advantages of high energy density, high powerdensity,discharge long cycle life and short time of charge,wide temperaturerange,etc.According to the characteristics of the ceramic capacitor, BaTiO₃ceramicsweredoped to modify and were coated to be studied in this paperthrough the solid phasemethod and liquid phase method. The main results are follows:（1） Doping rare earth to modifyBaTiO₃ceramics by solid phase method.The roomtemperature dielectric constant maximumof doping modifiedBaTiO₃-based ceramicscan reach450000. But when doping with Y2O₃alone, BaTiO₃-baseceramicshavelowresistivity, and should not be used for the actual. In order to improve the resistivityand reduce the dielectric loss, doping the material with Mn and Nb. Although whendopedwith Mn, Nb, ceramic material have relatively low dielectric loss, they alsohave relatively low dielectric constant, so improving dielectric properties bycoatingthe doping modified ceramic materialby liquid package method.（2） Then BaTiO₃-base powder was coated with SiO₂byliquid packagemethod.Preparing for SiO₂sol by liquid package method, and then coatingBaTiO₃-base powder with SiO₂sol. This paper studied the dielectricproperties andresistancevalue of the coating material. In keeping the material of high dielectricconstant premise improve material resistivity. In keeping high dielectric constant ofthe material and improve the resistivity.（3） BaTiO₃-base powder was coated with aluminum oxide by liquid packagemethod. The main objective is to improve the resistivity of BaTiO₃-base material andkeep high dielectric constant.