Low-temperature sintering of porous silicon carbide ceramic support with SDBS as sintering aid

The sintering temperature of porous silicon carbide ceramic support (PSCS) is typically higher than 1500 °C. In this paper, sodium dodecyl benzene sulfonate (SDBS) was used as a sintering additive to fabricate PSCS with high gas permeance and high bending strength at a sintering temperature less than 1200 °C. The PSCS was prepared by the dry pressing method followed by in-situ reaction. The effects of SDBS loading on the porosity, bending strength, gas permeation performance, and microstructure of the PSCS were investigated. The results showed that without SDBS, the required sintering temperature was as high as 1550 °C and resulted in a bending strength of 6.5 MPa but the sintering temperature decreased to 1150 °C with 8% SDBS and the bending strength increased to 16 MPa. The main reason was that SDBS decomposed into Na₂O which reacted with SiO₂ and ZrO₂ to form strong bonding connections. The prepared PSCS with SDBS also showed good gas permeance of 900 m³/(m² h kPa), higher than the 750 m³/(m²·h·kPa) without SDBS. This work describes the effective use of SDBS as a ceramic additive to reduce sintering temperature, while achieving high gas permeation and bending strength. The use of the low cost and commercially available SDBS produces an excellent ceramic filter with much lower energy consumption, and could also be implemented in other ceramic systems.