Preparation And Properties Of BaTiO₃ And CaCu₃Ti₄O₁₂/epoxy Dielectric Composites

Miniaturization and power efficiency of electronic devices is gaining intense interest in recent years.But until now,the reported dielectric constants of the ceramic/polymer composites are rather low.This work demonstrates that ceramic/polymer composites can achieve colossal dielectric constants by constructing three-dimensionally interwoven structures.Furthermore,the ceramic/polymer dielectric composites exhibit high mechanical strength using a novel approach,which consisting of the gelcasting,sintering and vacuum infiltration.The following part results were obtained:First of all,the best process factor for preparation process-gelcasting were explored,and the optimum parameters for AM-MBAM system were determined,（2）Ba TiO₃/epoxy composites via vacuum infiltration consisting of two three-dimensionally interpenetrating networks of BaTiO₃ and epoxy phases are prepared using the optimum parameters,found that the sintering temperature of ceramic skeleton controls their porosity,and when sintered at 1150℃,barium titanate/epoxy resin composite with the highest of BaTiO₃ solid content,up to 68vol.%,and with the highest?（28）1510 and the highest bending strength=127.6 MPa（3）The CCTO/Epoxy composite were prepared by the optimized gelcasting parameters.The pore structure of CaCu₃Ti₄O₁₂ ceramic skeleton was adjusted by sintering temperature.When the content of CaCu₃Ti₄O₁₂ was about 57.7vol%,the dielectric constant and bending strength of CaCu₃Ti₄O₁₂/epoxy composite reached the highest,respectively 1501 and 118.8 MPa.Because in composite material,CaCu₃Ti₄O₁₂ceramic particles form grain boundary,the dielectric constant is much higher than the existing theoretical model predicted value.In this thesis,an efficient and promising preparation method of ceramic/polymer composites was presented,and the prepared composite materials have excellent dielectric properties and high mechanical properties.