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Chloride‐Ion‐Stabilized Strontium Mayenite: Expansion of Versatile Material Family
Author(s) -
Dong Yingchao,
Hayashi Katsuro,
Nozoe Hiroki,
Shinoda Yutaka,
Hosono Hideo
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.13194
Subject(s) - materials science , spark plasma sintering , sintering , analytical chemistry (journal) , phase (matter) , rietveld refinement , evaporation , stoichiometry , ion , strontium carbonate , decomposition , crystal structure , strontium , crystallography , chemistry , metallurgy , physics , organic chemistry , chromatography , thermodynamics
Sr‐mayenite ( S 12 A 7 ) incorporating Cl − ions in its crystallographic cages up to the theoretical maximum occupancy, Sr 12 Al 14 O 32 Cl 2 , is reported in our study. The addition of a stoichiometric amount of SrCl 2 to the starting mixture is effective for the formation of Sr 12 Al 14 O 32 Cl 2 with high phase purity. Almost 100% densification is achieved using spark plasma sintering ( SPS ). Evaporation of SrCl 2 from Sr 12 Al 14 O 32 Cl 2 , which becomes significant at sintering temperatures above ~1300°C, degrades the phase purity. However, SrCl 2 effusion is significantly suppressed in the samples fully densified by SPS , impeding the decomposition of Sr 12 Al 14 O 32 Cl 2 up to temperature as high as ~1400°C. The crystal structure of Sr 12 Al 14 O 32 Cl 2 was investigated by Rietveld analysis of the X ‐ray diffraction pattern. It is found that the Cl − ion is incorporated in the center of the inner cage with nearly theoretical maximum occupancy, which is responsible for the phase stability. Porous Sr 12 Al 14 O 32 Cl 2 exhibits humidity‐sensitive surface protonic conductivity. Dense Sr 12 Al 14 O 32 Cl 2 prepared under reducing conditions such as SPS exhibits electronic conductivity. Sr‐mayenite has various potential applications derived from its multifunctionalities.