A Research Of Mg-Zn-Ti Ceramic For Microwave MLCC

Multilayer ceramic capacitor(MLCC)is a kind of passive devices used in the circuit,with advantages of small size,high capacity,high accuracy and high reliability.Today,the rapid development of electronic information,requiring smaller electronic equipment,worked in the high frequency even microwave frequency.Microwave MLCC has become an essential component of today's circuit.The selection of Mg-Zn-Ti system microwave ceramic dielectric ceramic materials as microwave ceramic material for MLCC in this work,to study the synthesis,doping and low-temperature sintering technology,the results prove that:(1)MgTiO3 and ZnTiO3 can form eutectic melt,and the change of MgTi O3 and ZnTiO3 content will affect the sintering temperature and dielectric properties of dielectric ceramics.When the content of ZnTiO3 is low,the sintering temperature of ceramics is higher.When the ZnTiO3 content is high,the impurity phase will be introduced,and it is easy to cause the phenomenon of over sintering.At the same time,the pre sintering temperature has a great influence on the performance of the ceramics,and whether the pre sintering temperature is suitable or not directly affects the performance of the final ceramic samples.(2)Ta2O5,CaF2 and CaTiO3 have a great influence on the properties of Mg-Zn-Ti dielectric ceramics,in which the proper doping of Ta2O5 can improve the quality factor of the ceramics,but too much addition will lead to more impurity.The addition of CaTiO3 does not react with the ceramic,which will affect the sintering and reduce the quality factor,but the frequency temperature coefficient can be adjusted and improve the dielectric constant.(3)H3BO3,LBS glass,BBS glass as sintering agent into Mg-Zn-Ti ceramics can effectively decrease the sintering temperature,the H3BO3 can help obviously to reduce the sintering temperature to 1000?,but H3BO3 will affect the electrode cofired with the ceramic.The glass is more stable,which does not affect the cofired with the electrode.BBS glass is suitable for batch production and high reliability.The study of different milling methods and different milling time on the particle size distribution of powder mixtures,which show that the planetary ball milling efficiency is high,but the size distribution is poor,the rolling ball milling efficiency is low,but the size distribution is appropriate.Through the above steps of Mg-Zn-Ti dielectric ceramics research,the microwave dielectric ceramics sintering at 1050?,dielectric properties is : ?r=22.1,Q×f =48740 GHz(at 6.5GHz),?f=-3.3ppm/oC,with good cofire with electrode.And the sample of MLCC,sintered at 1090?,the capacity value is about 100 pF,the deviation rate is between ± 4% and the dielectric loss is about 0.01%.