Reactions between Strontium‐Substituted Lanthanum Manganite and Yttria‐Stabilized Zirconia: II, Diffusion Couples

Abstract

Formation of secondary phases and diffusion of cations in diffusion couples of yttria-stabilized zirconia and lanthanum manganite substituted with 0 to 60 mol% strontium have been studied by scanning electron microscopy and energy dispersive X-ray spectroscopy. Only the primary phases were observed after 120 h at 1200°C, while formation of secondary phases was identified already after 1 h heat treatment at 1350°C. The phase composition of the reaction layer altered from La 2 Zr 2 O 7 to SrZrO 3 at increasing Sr content in La x Sr 1−x MnO 3 . The thickness of the reaction layer was increasing with heat treatment time. In diffusion couples of La 0.4 Sr 0.6 MnO 3 formation of manganese oxide was observed in the perovskite layer after 1 h heat treatment at 1350°C, while isolated grains of SrZrO 3 relatively deep inside the zirconia were observed after longer heat treatment time. Diffusion of Mn into zirconia was observed preferenced along grain boundaries in the early stage of the interface reaction.

High‐Performance SOFC Cathodes Prepared by Infiltration

“…[ [64][65][66][67] Most other conducting perovskites cannot be prepared in the relatively narrow temperature window that is required.…”

Effect of cathode and electrolyte transport properties on chromium poisoning in solid oxide fuel cells

“…The valence of manganese decreases upon dissolution into YSZ [59,60], such that there is more Mn 2+ than Mn 3+ [58,61]. Dissolution of manganese into YSZ from contact with LSM has been observed [62][63][64][65], and the manganese diffuses faster along the grain boundaries [57,[62][63][64]. The more rapid diffusion of manganese, relative to lanthanum, is the common explanation for the formation of the pyrochlore La 2 Zr 2 O 7 at the LSM/YSZ interface during processing [66][67][68][69][70][71].…”

Dispersion, connectivity and tortuosity of hierarchical porosity composite SOFC cathodes prepared by freeze-casting

“…22,23 To establish whether or not this phase is present within the composite material, X-Ray Diffraction (XRD) patterns were taken of sintered LSM-YSZ freeze-casts that had been crushed into a fine powder. Diffractograms were taken with an X'Pert Pro MPD diffractometer (PANalytical Company) with Bragg-Brentano Geometry and Copper K␣ wavelength of 1.5418Å.…”