Effects of Bi2O3 on the microstructure, mechanical strength, and dielectric properties of CaZnSi2O6 glass ceramics with machinable precursors

Abstract

Ceramizable silicone rubber composites were prepared using methyl vinyl silicone rubber, kilchoanite, low-melting-point glass frit, nano silica, and Bi2O3. CaZnSi2O6 glass ceramics were sintered at 1000 °C using ceramizable silicone rubber composites as the machinable precursors. The effects of Bi2O3 on the microstructure, mechanical strength, and dielectric properties of CaZnSi2O6 glass ceramics were studied. The results showed that the flexural strength of the ceramic samples first increased and then decreased with an increase in the Bi2O3 content. The maximum value of flexural strength was 110.48 MPa, which improved by 22% compared with that of the ceramic samples without Bi2O3. Bi2O3 provided more liquid phase, and the ceramic samples with Bi2O3 had a denser microstructure. Furthermore, Bi remained in the glass phase and increased the activation energy of relaxation polarization and conduction. The dielectric loss factor (tanδ) of the ceramic samples decreased with increasing Bi2O3 content, and the increase in tanδ with temperature was inhibited. Bi2O3 also improved the breakdown strength of the ceramic samples by 25%, from 22.54 to 28.12 kV/mm.