Structural Modification And Energy Storage Characteristics Of CaTiO₃-LnAlO₃?Ln=La,Nd,Sm? Ceramics

With the rapid development of the information technology.Microwave dielectric ceramics excellent characteristic is mainly dependent on high dielectric constant,high Q value and near zero resonance frequency temperature coefficient.It has been widely used in the microwave transmission,electronic warfare and other fields.Its multi-functional aspects has gradually been taken seriously because of the integration of electronic components and miniaturization requirements.In order to achieve multi-function device requirements,In this paper,CaTiO3-LnAlO3(Ln=La,Nd,Sm)microwave dielectric ceramics as the object which will be researched,by studying with the different rare earth elements,sintering additives and explore the sintering temperature interval,structure,dielectric properties and energy storage performance.(1)In this part,0.7CaTiO3-0.3LnA103(Ln=La,Nd,Sm)and(1-x)CaTiO3-xNdAlO3(x=0.1?0.5)microwave dielectric ceramics were prepared by solid-state reaction method,In preparation of 0.7CaTiO3-0.3LnA103(Ln=La,Nd,Sm)microwave dielectric ceramics,the different temperature,the change of its structure and performance is studied,when Ln=La,Nd,Sm,the cell volume gradually decreases and the crystal is a simple perovskite structure,the dielectric constant and Q·f value decreased gradually,when Ln=Nd,the energy storage density get the maximum value which is 0.161J/cm3.Microwave performance:?r=43.9,Q·f=34610GHz,?f=+2ppm/?.In preparation of(1-x)CaTiO3-xNdAlO3(x=0.1?0.5)microwave dielectric ceramics,when x=0.1-0.5,the dielectric constant decreased gradually,the Q·f value and energy density gradually increased.when x=0.5,the maximum energy storage density is 0.212J/cm3,and the microwave performance:?r=30.8,Q·f=50321GHz and ?f=-60ppm/?.(2)0.7CaTiO3-0.3NdAlO3(referred to as CTNA30)microwave dielectric ceramics has been Prepared.The cordierite glass(referred to as MAS)has been added in the ceramics materials.The change of its structure and performance is studied.With the increase of the amount of MAS,the unit cell volume of the material gradually increased,and the crystals are simple perovskite structure.when the amount of MAS is 5%,the sample get the best microwave performance:?r=42.4,Q·f= 12612GHz,if=+69ppm/?.The highest energy storage density was obtained by sintering at 1250? with 10%MAS glass.The energy storage density is 0.15J/cm3.(3)The polymer material(CE)was melted and then penetrated into the 0.7CaTiO3-0.3LnA103(Ln=La,Nd,Sm)and(1-x)CaTiO3-xNdAlO3(x=0.1?0.5)ceramic pieces,and then preparad the composite materials.The dielectric and energy storage properties were studied.In preparation of 0.7CaTiO3-0.3LnAlO3(Ln=La,Nd,Sm)/CE composites,The structural uniformity is perfect,when Ln=La,Nd,Sm,the highest energy storage density is 0.148J/cm3 in Ln=Nd,and the microwave performance:?r=15.7,Q·f= 1425GHz,and ?f=+265ppm/?.In preparation of(1-x)CaTiO3-xNdAlO3/CE composites,when x increases,the dielectric constant decreased gradually,while Q·f value is increased gradually.When x=0.2,the energy storage density can get to the maximum value,which is 0.285J/cm3,microwave performance:?r=19.1,Q·f=1310GHz,?f=+248ppm/?.