Study On Low-fired Ba₄(Nd_0.85Bi_0.15)_28/3Ti₁₈O₅₄ Microwave Ceramics

With the promotion of mobile communication industry, low-fired microwave ceramics has developed quickly. To meet material series requirement, not only the low-e materials but also high-e materials should be developed.Ba_6-3xLn_8+2xTi₁₈O₅₄ (Ln are Sm, Nd, La et al) plays an important role in mobile communication industry. It is a high-s material and can be used as key materials in multi-devices, such as filter, resonator. The achievements, microstructure and properties with different additive and sintering characteristics had been discussed in this paper. Based on the research of others, Ba₄(Nd_0.85Bi_0.1528/3Ti₁₈O₅₄was chosen to be studied.Ba₄(Nd_0.85Bi_0.1528/3Ti₁₈O₅₄ (BNT) microwave ceramics' microstructure and properties had been investigated, which used different additive method or added different additive or improvement of technical processes. The additives were BCC, BBS, ZnBiCu and PZBS. Technical process improvement was adding little (0.5^lwt%) BCC to BNT powder, which formed main crystal grain at lower sintering temperature.Based on technical process improvement, multi-additives could lower sintering temperature of BNT microwave ceramics efficiently. BNT microwave ceramics could be co-fired with Ag electrode, obtaining good dielectric properties and meeting the requirement of LTCC to make multi-devices. BNT microwave ceramics added BCC and BBS could be sintered at 890℃, the dielectric properties were s=63.8, Qxf=2253GHz, matching the requirement of production multi-filter.Solid solution was formed and BNT microwave ceramics could be sintered at 900℃ when BNT was co-fired with BBC/ZnBiCu multi-additives. BBC/ZnBiCu multi-additives could improve BNT ceramics' dielectric constant from 63.9 to 73.45. Dielectric properties of BNT ceramics including 5wt%ZnBiCu and 3.5wt%BCC additives were : 8=70.63,Q×f=2189GHz.PZBS was also studied to lower BNT sintering temperature and decrease technicalprocesses, avoiding the pollution of impurities. (Ba,Pb)Nd2TisOi4 solid solution was formed, which could improve BNT's dielectric properties. Dielectric properties of BNT ceramics including 0.5wt%BCC and 12wt%PZBS were : s = 80.95,Qxf= 1776GHz.