Effect of crystallization on microwave dielectric properties of stoichiometric cordierite glasses containing B₂O₃ and P₂O₅

The effect of crystallization on microwave dielectric properties of cordierite glasses containing B₂O₃ and P₂O₅ additions was investigated. Two glasses containing 5 wt% B₂O₃/5 wt% P₂O₅ and 7.5 wt% B₂O₃/7.5 wt% P₂O₅ were studied. Both glasses were sintered to nearly full density at temperatures as low as 860 °C. The frequency constant and quality factor of α cordierite are, respectively, about five times and two times larger than those of glassy phase and μ cordierite. The temperature coefficients of resonant frequency are estimated to be about −13, −55, and −15 ppm/°C for glassy phase, μ cordierite, and α cordierite, respectively. As a result of the microwave dielectric properties of the individual phase, cordierite glasses containing α cordierite possess the best microwave properties.