Study On Modification Of Microwave Dielectric Ceramic Material Ba₂Ti₉O₂₀

Ba2Ti9O20(B2T9) is a high-performance intermediate frequency microwavedielectric ceramic material, but because of high sintering temperature, it has been verydifficult to obtain a wide range of applications. In this paper, the change in rawmaterial particle size and doping modification method are used to make modificationon the microwave dielectric ceramic material, B2T9. I committed to reduce B2T9’ssintering temperatures, maintaining its good dielectric properties.In this paper, powder BaCO3and small particle size powder BaTiO3weresynthesized in advance B2T9respectively, then Y glass doping. The results showedthat the synthetic method of B2T9with the particle size of100nm BaTiO3as the rawmaterial of synthesis has an at least200oC lower sintering temperature than theformer method. When the concentration of B2T9is4wt%of Y doped and thesintering temperature is980oC, B2T9can have the value of the dielectric constant of40, temperature coefficient of dielectric constant=-3600, dielectricloss tan=2×10-4. In addition to its large temperature coefficient, the parameters aremaintained B2T9’s original fine features. It already reached the level of low-gradefever.This paper also made a initial systematic research on glass doped for B2T9. Fiveglass prepared by mixing B2O3, CuO, MnO2, were adoped in this process. The resultshowed that:B2O3and CuO have the ability to promote low-temperature sintering of B2T9microwave dielectric ceramics;When the B2T9doped with8wt%B2O3, sintered at1060oC, it can achieve arelatively low dielectric loss with the value of tan=3×10-4, and the value of dielectricconstant=19.CuO alone is not suitable to be the modified dopant for B2T9’s low temperaturesintering. But the combination of CuO-MnO2glass was able to get good results.B2T9doped with2wt%of CM, and sintered at1080oC, can have a relatively lowdielectric loss tan=3×10-4， it can have the value of the dielectric constant of42， temperature coefficient of dielectric constant-3600×10-6/°C, dielectricloss2×10-4. BCB (2BaO-2CuO-B2O3) performed well in B2T9modifiedglass。B2T9dopedwith2wt%of BCB, and sintered at1040oC, can have a relatively low dielectric losstan=2.5×10-4， it can have the value of the dielectric constant of37， temperaturecoefficient of dielectric constant=3×10-6/°CAt the micro structure, BCB’s adjunction can control the size of the grains.Small amount of BCB doping on can promote B2T9’s crystal growth. When thedoping amount is more than a certain limit (6wt%), BCB will also inhibit grain’sgrowth. When the doping amount is a certain level, grain size will be a certain value,which is independent of temperature...