Low-temperature fabrication of steatite ceramics with boron oxide addition

Steatite ceramics have been fabricated by using coarse starting materials such as talc, clay, and barium carbonate with addition of boron oxide (B2O3). B2O3 has been found to be a useful flux to densify MgO–Al2O3–SiO2–BaO (MASB) powders. The steatite ceramic with a relative density of 97% was obtained at a sintering temperature of 1200 °C. The temperatures needed to densify MASB powders decrease with increase of B2O3 addition. For the same sintering temperature, as the amount of B2O3 addition increases, the crystallization rate of protoenstatite increase. Large pores and visible cracks were seen in B2O3-free samples, while pore elimination and enhancement of densification for B2O3-added steatites were promoted by the viscous flow due to B2O3. Hence, nearly dense ceramics were obtained for use in high temperature electrical applications.