Study Of MgTiO₃-ZnTiO₃-CaTiO₃System MLCC Ceramics And Pilot Production

The sintering temperature serialization,pilot production,and MLCC serializationof MgTiO₃-ZnTiO₃-CaTiO₃（MZC） system ceramics were studied.MgTiO₃-ZnTiO₃（MZ） system and CaTiO₃ceramics with mutual-compensatedtemperature coefficients of capacitance（-55℃～125℃） have low dielectric loss athigh frequency.By addition of appropriate amount of CaTiO₃,sintering system,andmilling technology,the microstructure and phases were altered so that excellentdielectric properties were obtained at high sintering temperature. CaTiO₃not only canadjust the relative dielectric constant （ε_r） and the temperature coefficient ofcapacitance（TCC）,but also can inhabit the abnormal growth of MZ grain.The sizedistribution curve of MZC ceramic powder was influenced by milling time andmilling medium significantly.The addition of ZnO-H₃BO₃（GD） composite oxide and Li₂O₃-B₂O₃-SiO₂（G4）can decrease the sintering temperature of MZC ceramic, so that middle and lowtemperature sintering were obtained. GD composite oxide can form liquid phase atintermediate sintering temperature and promote the formation of CaTiO₃grain.Besides surplus glass phase can promote the transformation from Mg₂TiO₄toMgTiO₃. At low sintering temperature, Zn²⁺can be replaced by Mg²⁺by increasingG4composite oxide,which can inhabit the some transformation from ZnTiO₃toZn₂TiO₄.By contrast, a large amount of surplus G4glass phase can promote theformation of Zn2Ti3O8from ZnTiO₃. The morphology of G4and milling medium alsoaffected the phases of system.By control of formula、process、and dielectric properties, The MZC ceramicswere obtained at high\intermediate\low sintering temperature.（1） The MZC ceramic doped with1.3mol%CaTiO₃sintered at1270℃for2hhad excellent dielectric properties of=22.62, tan=1.3×10-5, TCC=20.51ppm/℃（-55℃～125℃）.（2） The MZC ceramic doped with8.25wt%GD glass sintered at1110℃for2hhad excellent dielectric properties of=22.38,=1.7×10-5, TCC=20.93ppm/℃（-55℃～125℃）.（3） The MZC ceramic doped with10.0wt%G4glass sintered at900℃for8hhad excellent dielectric properties of=20.88,=9.5×10-5, TCC=15ppm/℃（-55℃～125℃）.For the research of pilot production and MLCC about MZC ceramics, The size distribution curve of MZC ceramic powder were almost not influenced by the processfrom preliminary examination to pilot production.Compared to disk,the sinteringtemperature of MLCC was lower and dielectric properties were decreased to someextent,which was caused by impefect match between ceramics and electrodes.