Influence of multi-component glass on sintering behavior and microwave properties of Zr non-stoichiometricly substituted Ca[(Li1/3Nb2/3)]O3-δ ceramic

A low melting point multi-component glass (Li2O-B2O3-SiO2-CaO-Al2O3) was incorporated into Zr non-stoichiometric substituted Ca[(Li1/3Nb2/3)]O3-delta ceramic to lower its sintering temperature for LTCC applications. The glass acts as liquid phase sintering aid and it can lower the sintering temperature of the ceramic from 1,170 A degrees C to 900 A degrees C. Dense and perovskite solid solutions can be obtained in all glass doped specimens with, however, a small amount of Ca2Nb2O7-type pyrochlore phase. Raman spectra indicate that the B-site 1:2 ordering structure in Ca[(Li1/3Nb2/3)(0.95)Zr-0.15]O3+delta ceramic is gradually softened with the increase of the glass content and localized B-site 1:1 ordering domains begin to appear when the glass content reaches 15 wt%. The optimal microwave dielectric properties of epsilon(r) = 29.37, Qf = 5,420 GHz and tau(f) = -24.9 ppm/A degrees C can be obtained in 5 wt% glass doped Ca[(Li1/3Nb2/3)(0.95)Zr-0.15]O3+delta ceramic when sintered at 940 A degrees C for 4 h. No chemical reaction exists between Ag and the above ceramic, which indicates itself a potential candidator in LTCC industry.