ZBAS on the Structure and Dielectric Property of BaAl2Si2O8

Barium feldspar BaO-Al2O3-SiO2 system materials have been studied widely for satellite communication, microwave substrate and packaging in recent years. BaAl2Si2O8-x(ZnO-Al2O3-SiO2-B2O3) (x=0, 1%, 2%, 3%, 4%) ceramics were prepared by solid state route. The effects of ZBAS glass on the sintering behaviour, phase composition and microwave dielectric properties of BaAl2Si2O8 were investigated. Addition of ZBAS glass can effectirely lower the sintering temperature to 1360 degrees C without changing phase composition of the sample and greatly propel the transition from hexacelisian to celsian. When x >= 2%, the transition from hexacelisian to celsian reaches 100%. Density, dielectric constant and tau(f) of BaAl2Si2O8-ZBAS ceramics increase with the increment of ZBAS glass in the range of 1% <= x <= 4%. In addition, the resonant frequency temperature coefficient is negative. The BaAl2Si2O8-ZBAS sintered at 1360 degrees C obtains a high Qxf of 28058 GHz, epsilon(r) =6.72 and tau(f)=-29.79 X 10(-6)degrees C-1 at x=3%. Deviations between experimental and theoretical relative permittivity of BaAl2Si2O8-xZBAS is also discussed.