One-step co-sintering of SiC ceramic membranes for gas filtration under high temperature

Abstract

Silicon carbide (SiC) ceramic membranes, with superior qualities, have been emerged as an excellent choice for gas/solid filtration under extreme conditions. However, the traditional SiC membranes generally consist of a multi-layer structure, which not only decreases gas permeance but also leads to high fabrication cost. In this study, a defect-free SiC ceramic membrane without intermediate layer was successfully prepared through a strategy combined pre-filling strategy and co-sintering process. The polyvinyl butyral (PVB) solution was introduced to pre-fill the pores of the “green” SiC support, which successfully prevented membrane layer particles from penetrating. The “green” support surface was then coated with the membrane layer dispersion by tape-casting, followed by a co-sintering process. During the process, PVB would decompose at high temperature. The optimized membrane exhibited a mean pore size of approximately 2.7 μm. The membrane layer thickness reached ∼200 μm, corresponding to a measured gas permeance of 230 m³ ·m⁻² ·h⁻¹·kPa⁻¹. Furthermore, during high-temperature filtration experiments at 400 °C with mixed particles of various sizes (from 50 nm to 2 μm), the membrane displayed outstanding gas/solid filtration performance, exceeding 99.9%, while retaining a low pressure drop under 1.81 kPa. In summary, the proposed approach offers an effective pathway to fabricate SiC membranes with both high permeance and satisfied filtration efficiency under extreme conditions.