Study On Low Temperature Sintering And Dielectric Properties Of Li₃Mg₂NbO₆ Microwave Dielectric Ceramics

In recent years,the development of low temperature ceramic co-firing technology?LTCC?has attracted more and more attention of researchers.It uses high conductivity metal electrodes such as silver and ceramic co-firing to achieve miniaturization of electronic devices.However,most of the microwave dielectric ceramics sintering temperature higher than melting point?961°C?of silver?Ag?,can not be co-fired with silver electrode.Therefore,it is very important to reduce the sintering temperature of microwave dielectric ceramics.In this paper,the effects of processing parameters on the phase,microstructure and dielectric properties of Li₃Mg₂NbO₆ were explored,such as the pre-sintering temperature,the second milling time and sintering temperature.It is reported that the sintering temperature of the pure phase Li₃Mg₂NbO₆ was 1250°C,much higher than961°C.In order to realize low temperature sintering,we chosen Li₃Mg₂NbO₆ with1.0wt%LBS as the research target.In order to decrease the sintering temperature of Li₃Mg₂NbO₆,LBS,MBS,ZBS and B₂O₃ additives were added.Effects of various sintering additives on the phase,microstructure and microwave dielectric properties of Li₃Mg₂NbO₆ have been investigated.Li₃Mg₂NbO₆+1.0wt%LBS sintered at 875°C show good microwave dielectric properties of?_r=14.89,Q×f=86,720 GHz,?_f=-15.46 ppm/°C.Li₃Mg₂NbO₆+0.5wt%MBS sintered at 925°C show good microwave dielectric properties of?_r=14.5,Q×f=80,759 GHz,?_f=-20.7 ppm/°C.Li₃Mg₂NbO₆+0.5wt%ZBS sintered at925°C show good microwave dielectric properties of?_r=14.3,Q×f=73,987 GHz,?_f=-16.5 ppm/°C.Li₃Mg₂NbO₆+0.1wt%B₂O₃ sintered at 925°C show good microwave dielectric properties of?_r=14.0,Q×f=67,451 GHz,?_f=-16.82 ppm/°C.In addition,this paper also studies the Mg²⁺ion substitution(Ca²⁺,Ni²⁺,Zn²⁺,Mn²⁺)of Li₃Mg₂NbO₆.Li₃(Mg_0.95Ca_0.05)₂NbO₆ can obtain excellent microwave dielectric properties of?_r=15.6,Q×f=96,160 GHz,?_f=-18.49 ppm/°C.