Abstract
The effects of Li 2 O-ZnO-B 2 O 3 (LZB) glass addition on densification and dielectric properties of Ba 4 (Nd 0.85 Bi 0.15 ) 9.33 Ti 18 O 54 (BNBT) have been investigated. At a given ratio of ZnO/B 2 O 3 , the glass softening point decreases, but the thermal expansion coefficient and dielectric constant increase with increasing Li 2 O content in the LZB glass. With 10 vol% LZB glass, the densification temperature reduces greatly from 1300°C for pure BNBT to 875°C-900°C for BNBT + LZB dielectric, and the densification enhancement becomes more significant with increasing Li 2 O content in the LZB glass. The above result is attributed to a chemical reaction taking place at the interface of LZB/BNBT during firing, which becomes less extensive with increasing Li 2 O content in the LZB glass. Therefore, more residual LZB glass, which acts as a densification promoter to BNBT, is left with increasing Li 2 O content. For the LZB glass with a Li 2 O content in the range 10-30 mol%, the resulting 90 vol% BNBT + 10 vol% LZB microwave dielectric has a dielectric constant of 55-70, product (Q × f r ) of quality factor (Q) and resonant frequency (f r ) of 1000-3000 GHz at 5-5.79 GHz, and a temperature coefficient of resonant frequency (τ f ) of 10-60 ppm/°C in the temperature range between 25°C and 80°C. © 2013 The American Ceramic Society.