Dual-phase membrane composed of oxide ion conductor and electron conductor was fabricated for application to oxygen separation membranes. 8 mol% yttria-stabilized zirconia (8YSZ) and carbon felt were used for the oxide ion conducting phase and the electron conductiing phase, respectively. Carbon felt was impregnated with YSZ aqueous suspension (40 wt%), dried, then sintered by a spark plasma sintering (SPS) process under the applied pressure of 80 MPa at 1200, 1400 and 1600 ° C for 10 min. When sintered at 1600 ° C, the XRD pattern showed small peaks indicating the formation of the zirconium carbide phase, but the microstructure observed by SEM showed that the YSZ was well densified and tightly bonded with carbon felt. This method has been demonstrated to be an effective process for the fabrication of YSZ-Carbon composites with both phases percolation structure.

A dual-phase membrane composed of an oxide ionic conducting ceramic phase [8 mol % yttria-stabilized zirconia (8YSZ)] and electronic conducting metal phase [316L stainless steel (SS)] was fabricated for an oxygen separation application. A sintering process called spark plasma sintering (SPS) or pulsed electric current sintering (PECS) was chosen as the means to densify the 8YSZ phase below the melting point of the SS phase. The SS content was varied from 15 vol % to 55 vol % to achieve a percolation structure for obtain the oxygen transport activity. Silver paste was applied to both sides of the membrane to act as a catalyst to improve the oxygen exchange rate. In this research study, a free-standing dense 8YSZ-SS dual-phase membrane with a thickness of 0.5 mm was fabricated by SPS at 1200 °C and the applied pressure of 80 MPa in 10 min. The 8YSZ-SS45 vol % dual-phase membrane achieved a good percolation structure of the 8YSZ and SS phases. By applying silver paste, 8YSZ-SS45 vol % dual-phase membrane exhibited the reasonably good oxygen permeation flux of 1.38 ml (STP)/min•cm 2 at 900 °C.