Research On Structure And Microwave Dielectric Properties Of Li₂Mg₃TiO₆ Ceramics Systerm

Microwave dielectric ceramic is an important part of the microwave device and has significant effects on the development of microwave communication.Li₂Mg₃TiO₆ceramics is a promising ceramic material,which have excellent microwave dielectric properties and low cost of raw materials.In this paper,the sintering technique,microscopic structures and microwave dielectric properties of Li₂Mg₃TiO₆ dielectric properties system were investigated systematically.The main contents of the paper are as follows:In this paper,Li₂Mg₃TiO₆ ceramics was fabricated using a conventional solid-state reaction method,the effects of laminated sintering technique on the microwave dielectric properties of Li₂Mg₃TiO₆ ceramics were discussed.We found that this technique couud reduce the pores and evaporation of Li,and increase the density of ceramics.The Li₂Mg₃TiO₆ ceramics using laminated sintering technique had excellent microwave dielectric properties of?_r¹3.2,Q×f¹56,000GHz and?_?^-31.3ppm/?.The A-ite and B-site irons of Li₂Mg₃TiO₆ ceramics were substituted by different irons.It was found that the substitution of Ca²⁺and Zn²⁺for Mg²⁺could decrease temperature coefficient of resonant frequency.In addition,the substitution of Co²⁺for Mg²⁺could improve Q×f values of Li₂Mg₃TiO₆ ceramics to 165,000GHz,while the substitution of Sn⁴⁺for Ti⁴⁺could improve Q×f values of Li₂Mg₃TiO₆ ceramics to168,000GHz.However,the substitution of Mn²⁺and Ni⁴⁺could reduce Q×f values of Li₂Mg₃TiO₆ ceramics.The effects of polarizabilities,packing fractions,bond valence,bond energies on microwave dielectric properties in Li₂Mg_3-xCo_xTiO₆ ceramics were also discussed.The ZBS and LBS glass were added to Li₂Mg₃TiO₆ ceramics to lower the sintering temperature.Li₂Mg₃TiO₆ ceramics with 4wt%ZBS glass sintered at 1025?displayed excellent microwave dielectric properties of?_r¹3.35,Q×f¹38,800GHz and?_?³1.84ppm/?.Moreover,the sintering behavior and microwave dielectric properties of Li₂A_xTiO_3+x?2?x?4,A=Mg,Ni?ceramics were discussed through analyzing the structure of Li₂Mg₃TiO₆ ceramics.It was suggested that this ceramics system hadthe similar structure with MgO and a small temperature coefficient of resonant frequency.Li₂Mg_3.6TiO_6.6 ceramics sintered at 1375?had good microwave dielectric properties of?_r¹2.7,Q×f¹69,000GHz,?_?^-32.8ppm/?.