Graphite and PMMA as pore formers for thermoplastic extrusion of porous 3Y-TZP oxygen transport membrane supports

• Published in: Journal of the European Ceramic Society Vol. 37; no. 3; pp. 1039 - 1047
• Main Authors: Haugen, Astri Bjørnetun, Gurauskis, Jonas, Kaiser, Andreas, Søgaard, Martin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2017
• Subjects: Gas permeability; Oxygen transport membranes; Porosity; Thermoplastic extrusion; YSZ; Gas permeability; YSZ; Porosity; Thermoplastic extrusion; Oxygen transport membranes
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2016.10.001

A gas permeable porous support is a crucial part of an asymmetric oxygen transport membrane (OTM). Here, we develop feedstocks for thermoplastic extrusion of tubular, porous 3Y-TZP (partially stabilized zirconia polycrystals, (Y2O3)0.03(ZrO2)0.97)) ceramics, using graphite and/or polymethyl methacrylate (PMMA) as pore formers. The influence of pore former content and type, 3Y-TZP particle size and support sintering temperature on the microstructure, porosity and gas permeability were studied. Using at least 40 vol% pore former, consisting of graphite and PMMA in the volume ratio 2:1, tubes with gas permeability exceeding the target of 10−14m2 are obtained. In the temperature range 1250–1400°C the support gas permeability is insensitive to the sintering temperature, and the feedstocks shrink more than 15% during sintering, making them ideal for co-sintering with functional OTM layers. This demonstrates the suitability of thermoplastic extrusion for fabrication of porous 3Y-TZP OTM supports, or for other technologies requiring porous ceramics.