Chloride‐Ion‐Stabilized Strontium Mayenite: Expansion of Versatile Material Family. Issue 12 (22nd August 2014)

• Record Type: Journal Article
• Authors: Dong, Yingchao; Hayashi, Katsuro; Nozoe, Hiroki; Shinoda, Yutaka; Hosono, Hideo; Vanderah, T.
• Is Part Of: Journal of the American Ceramic Society. Volume 97:Issue 12(2014)
• Page Start: 4037
• Page End: 4044
• Publication Date: 2014-08-22
• Subjects: Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.13194
• Languages: English
• ISSNs: 0002-7820

Abstract

<abstract abstract-type="main" id="jace13194-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Sr‐mayenite (S<sub>12</sub>A<sub>7</sub>) incorporating Cl<sup>−</sup> ions in its crystallographic cages up to the theoretical maximum occupancy, Sr<sub>12</sub>Al<sub>14</sub>O<sub>32</sub>Cl<sub>2</sub>, is reported in our study. The addition of a stoichiometric amount of SrCl<sub>2</sub> to the starting mixture is effective for the formation of Sr<sub>12</sub>Al<sub>14</sub>O<sub>32</sub>Cl<sub>2</sub> with high phase purity. Almost 100% densification is achieved using spark plasma sintering (SPS). Evaporation of SrCl<sub>2</sub> from Sr<sub>12</sub>Al<sub>14</sub>O<sub>32</sub>Cl<sub>2</sub>, which becomes significant at sintering temperatures above ~1300°C, degrades the phase purity. However, SrCl<sub>2</sub> effusion is significantly suppressed in the samples fully densified by SPS, impeding the decomposition of Sr<sub>12</sub>Al<sub>14</sub>O<sub>32</sub>Cl<sub>2</sub> up to temperature as high as ~1400°C. The crystal structure of Sr<sub>12</sub>Al<sub>14</sub>O<sub>32</sub>Cl<sub>2</sub> was investigated by Rietveld analysis of the X‐ray diffraction pattern. It is found that the Cl<sup>−</sup> ion is incorporated in the center of the inner cage with nearly theoretical maximum occupancy, which is responsible for the phase stability. Porous Sr<sub>12</sub>Al<sub>14</sub>O<sub>32</sub>Cl<sub>2</sub> exhibits humidity‐sensitive surface protonic conductivity. Dense Sr<sub>12</sub>Al<sub>14</sub>O<sub>32</sub>Cl<sub>2</sub> prepared under reducing conditions such as SPS exhibits electronic conductivity. Sr‐mayenite has various potential applications derived from its multifunctionalities.</p> </abstract>