Research On Microwave Dielectric Properties Of MgTiO₃-Based Ceramic

MgTiO₃ ceramic is a typical microwave dielectric material with high quality factor, rich source of raw materials, low cost and wide applications. However, MgTiO₃ ceramic has high sintering temperature, low dielectric constant and large absolute value of resonant frequency temperature coefficient, which limit its wide application in some field. Therefore, the key research question is lowing the sintering temperature and improving the dielectric properties of MgTiO₃ ceramics.?1-x?MgTiO₃-xBaTiO₃ ?MBT? and ?1-y? MgTiO₃-yCaTiO₃ ?MCT? ceramic were prepared by solid phase reaction. The relationship among ceramic composition, sintering process and properties was investigatied. Microstructure and phase composition were analysized by scanning electron microscopy ?SEM?, energy disperse spectroscopy ?EDS? and X-ray diffraction ?XRD?, and the dielectric properties were explored by using network analyzer. ZnO and Fe₂O₃ were doped into MCT to adjust microwave dielectric properties of materials.The results show that after MgTiO₃ compositing with BaTiO₃ and CaTiO₃ respectively, with increasing Ba and Ca content, ?r and ?f were increaing, Q·f was decreasing; when added with 0.07mol CaTiO₃, ?f value of the material was near to zero, ?f=0.652ppm/?, dielectric constant:?f=19.45?quality factor:Qf=38753GHz.After doping ZnO and Fe₂O₃ into MCT, ?r value of the material was increased slightly and sintering densification temperature was reduced substantially when the premise of ceramic's ?r near zero. When doped with 0.015mol Fe₂O₃, it can obtain microwave dielectric ceramic with highest relative density and excellent properties sintering at 1290? for 4h, the highest relative density is 99.49%, the dielectric properties as follows:?r=21.32,Q·f=37448GHz, ?f=-2.308ppm/?In this experiment, it can obtain MgTiO₃-based microwave dielectric ceramic with excellent dielectric properties through compositing, doping and improving the sintering process.