Characteristics and dielectric properties of ZrO2-doped calcium borosilicate glass-ceramics

Abstract The influence of zirconium dioxide (ZrO2) content on crystallization, densification, and dielectric performance of calcium borosilicate (CBS) glass-ceramics was systematically investigated by differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and electrical measurements. The results revealed that ZrO2 doping reduced the crystallization temperature of CBS glass-ceramics and introduced crystalline phase of another impurity; however, excessive ZrO2 led to an increase in the crystallization temperature. Furthermore, the increase of ZrO2 content promoted the precipitation of wollastonite crystal phase. However, excessive ZrO2 damaged the close arrangement of wollastonite crystal grains in the microstructure and weakened the dielectric properties of the CBS glass-ceramics. Under optimal sintering conditions, the CBS glass-ceramics with molar ratio of n(Ca):n(Si):n(B) = 1:1:0.6 and ZrO2 content of 1 wt.% resulted in dielectric constants of 3.6 and 3.7 and a dielectric loss of 2.9 × 10−3 and 6.1 × 10−3 at 1 and 10 MHz, respectively.