Preparation And Research Of SiO₂-based And Silicate Microwave Dielectric Ceramic Substrates

With the development of communication,aerospace and other fields,people's research on microwave dielectric ceramics has also developed rapidly with the increase of their demand.As a material for microwave dielectric ceramic substrates,a dielectric constant <15,a high quality factor,and a temperature coefficient of resonance frequency tending to zero are required.The size of the microwave device decreases with the increase of the dielectric constant.To reduce the size of the microwave device,the dielectric constant of the material system needs to be increased.SiO₂,silicate and other materials are low dielectric constant materials,which have good dielectric and mechanical properties.Therefore,this paper uses hot pressing and pressureless sintering methods to prepare microwave dielectric ceramics with dielectric constants of 6,12 and certain mechanical properties using SiO₂,Zn2 Si O4 and Mg2 Si O4 as matrix materials.Using threepoint bending,the mountain incision beam method was used to measure its mechanical properties;the high-Q cavity method was used to measure its dielectric constant;and the scanning electron microscope was used to observe its morphology.The dielectric constant of SiO₂ is 3.9.Using the method of hot pressing sintering,SiO₂ is used as the matrix,and the dielectric constant of CaTiO₃ with large dielectric constant and positive temperature coefficient of resonance frequency is added to increase the dielectric constant of the SiO₂ material system.The XRD analyte phase composition analyzed the reaction between SiO₂ and CaTiO₃,and explored the reaction temperature of SiO₂ and CaTiO₃,and the effect of CaTiO₃ addition on the reaction.As the amount of CaTiO₃ added increased,the reaction became easier;at the same time,the dielectric constant of the material also increased,and the dielectric constant of the material system was successfully increased to 6.0.However,the mechanical properties of the material system are poor,and it is difficult to meet the demand for mechanical properties in actual production.Using pressureless sintering method,using Zn2 Si O4 as the matrix,adding sintering aid to reduce the sintering temperature of the material,so that the material can be densified and sintered at a lower temperature,the relevant performance of the prepared material system is tested,and the performance of the material is analyzed.A microwave dielectric ceramic with a dielectric constant of 6 and good mechanical properties was prepared.Using pressureless sintering method,using Mg2 Si O4 as the matrix,adding a sintering aid to reduce the sintering temperature of the material system,and adding a low dielectric constant material Zn Ti O3 with better dielectric properties to complete the dense sintering at a lower temperature to improve the material Dielectric constant,analyze the relevant properties of the material,and prepare a microwave dielectric ceramic with a dielectric constant of 12 and good mechanical properties.