Low-temperature sintering of CaZnSi₂O₆ glass ceramics with machinable precursor based on silicone rubber

The applications of ceramics are limited by their high sintering temperatures and poor processability. The ceramizable silicone rubber composites were prepared using kilchoanite as a ceramic filler, low-melting-point glass frit as a flux, and nano SiO₂ as a reinforcing agent. The CaZnSi₂O₆ glass ceramics were sintered at 1000℃ using the ceramizable composites as machinable precursors. The effect of the mass fraction of silicone rubber and the content of glass frit on the mechanical properties of the ceramics was studied. The effect of Bi₂O₃ as a secondary flux on the microstructure, flexural strength and dielectric properties of the ceramics was investigated. The results show that the flexural strength of the ceramic samples increase first and then decrease with reducing the mass fraction of silicone rubber or increasing the content of glass frit. The maximum flexural strength of the ceramic samples without Bi₂O₃ sintered at 1000℃ is 90.54 MPa, and the linear contraction is only 15%. A proper content of Bi₂O₃ not only improve the density of microstructure and increase the flexural strength to 110.48 MPa, but also decrease the tanδ of the ceramics at power frequency and high temperature obviously, and improve the breakdown strength of the ceramics at power frequency. The precursors in this study have a good processability and could complete the sintering of ceramics with different sizes and shapes.