Microstructure and properties of calcium borosilicate and borosilicate glass-ceramic composites

Calcium borosilicate (CaO-B₂O₃-SiO₂, CBS) glass based glass-ceramic composites were prepared by introducing borosilicate glass. The effects of borosilicate glass and firing temperature on the microstructure and properties of the glass-ceramic composites were investigated. The results showed that the composites containing 0-40% (in mass fraction, the same below) borosilicate glass can be sintered at 850°C. The dielectric constant (ε_r) decreases with the increase of borosilicate glass content and can be adjusted in the range of 5.6-6.6. The coefficient of thermal expansion (CTE) increases with the increase of borosilicate glass content. Increasing sintering temperature favors the precipitations of crystal phases, which have lower ε_r than CBS glass, resulting in the decrease of ε_r for the composites.