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Directionally Solidified Eutectics: Selected Papers from DSEC IV. ; Al2O3-Er3Al5O12-ZrO2 eutectic ceramic rods were directionally solidified using the laser floating zone method at different growth rates, 25, 350 and 1200mm/h. The microstructure obtained, in terms of both morphology and phase size, was strongly dependent on the growth rate. However, electron backscatter diffraction experiments showed that the growth directions were the same for all the processing rates, [0001]Al2O3//[100]EAG//[100]ZrO2. The microstructural stability was investigated up to 1600°C as a function of the growth rate. Ceramics with the largest phase size presented high stability, their microstructure remaining substantially unchanged at the highest annealing temperature for 100h. Eutectics processed at higher growth rates and with a finer microstructure showed coarsening after heat treatments. The sample grown at 350mm/h coarsened at 1450°C whereas the eutectic solidified at 1200mm/h thickened at 1400°C. The growth directions remain unaffected for all growth rates. The mechanisms of microstructural coarsening were investigated. © 2014 Elsevier Ltd. ; The authors acknowledge the financial support from the Ministerio de Ciencia e Innovación de España and from the FEDER funds of the European Community under project MAT2009-13979-C03-03. The authors would like to acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza. S. Serrano-Zabaleta thanks the Spanish Government for a grant and M.C. Mesa also thanks the Gobierno de Aragón for a grant. ; Peer Reviewed

Temporary Removal. ; Composite molten salt-ceramic membranes are promising devices for high-temperature CO2 separation. Intensive material properties impact on separation performance as do membrane geometry (thickness) and microstructure (pore volume fraction, size, connectivity, and tortuosity factor). Although controlling pore size is considered somewhat routine, achieving pore alignment and connectivity is still challenging. Here we report the production of the first gas separation membrane using a porous ceramic matrix obtained from a directionally-solidified magnesium-stabilised zirconia (MgSZ) – MgO fibrilar eutectic as the membrane support. MgO was removed from the parent material by acid-etching to create a porous matrix with highly aligned pores with diameters of ~1 μm. X-ray nano-computed tomography of a central portion (~32,000 μm3) of the support identified ~21% porosity, with all pores aligned within 10° and ~76% percolating along the longest sampled length. Employing the matrix as a support for a carbonate molten salt, a high CO2 permeability of 1.41x10-10 mol.m-1.s-1.Pa-1 at 815 °C was achieved, among the highest reported for supported molten-carbonate membranes (typically 10-12 to 10-10 mol.m-1.s-1.Pa-1 at similar temperatures). We suggest that the high permeability is attributable to the excellent pore characteristics resulting from directional solidification, namely a dense array of parallel, micron-scale pores connecting the feed and permeate sides of the membrane. ; The authors acknowledge the financial support from the Spanish Ministerio de Economía y Competitividad and Feder Funds under project MAT2016-77769R. L. Grima acknowledges financial support through grant BES-2017-079683 associated to the aforementioned project. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement Number 320725 and from the Engineering & Physical Sciences Research Council (EPSRC) via grants EP/M01486X/1, EP/P007767/1 and EP/P009050/1. PRS acknowledges the Royal Academy of Engineering (CiET1718/59). PRS, DJLB, JJB and MDK acknowledge the support of The Faraday Institution (faraday.ac.uk; EP/ S003053/1). G. Mutch was supported by the Royal Academy of Engineering under the Research Fellowship Scheme and would like to thank the EPSRC for his Doctoral Prize Fellowship (EP/M50791X/1) and Newcastle University for a Newcastle University Academic Track (NUAcT) Fellowship. X-Ray CT acquisition and analysis was supported by UCL and EPSRC under EP/N032888/1. We thank the Servicio General de Apoyo a la Investigación-SAI (Universidad de Zaragoza) for technical support in X-ray diffraction and electron microscopy experiments, Rubén Gotor for technical assistance in sample preparation and R. Lahoz for laser-drilling the YSZ plate that serves as the membrane base. ; Peer reviewed