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The aluminum-rich part of the system BaO-Al{sub 2}O{sub 3}-MgO. 1: Phase relationships

Journal Article · · Journal of Solid State Chemistry
;  [1];  [2]
  1. RWTH, Aachen (Germany). Inst. fuer Kristallographie
  2. National Inst. for Research in Inorganic Materials, Tsukuba, Ibaraki (Japan)
The subsolidus phase relations in the Al-rich part of the system BaO-Al{sub 2}O{sub 3}-MgO at 1,800 C in air have been determined. The hexaaluminate phases in this part of the system all exhibit {beta}-alumina structure types. In the binary system BaO-Al{sub 2}O{sub 3}, the phases Ba{sub 1.21}Al{sub 11}O{sub 17.71} and Ba{sub 0.75}Al{sub 11}O{sub 17.25} were confirmed. In the ternary system, two solid solution series, BAM-I and BAM-II, exist. The solid solution range of BAM-I between the defect-free {beta}-alumina end member BaMgAl{sub 10}O{sub 17} and the Mg-free end member Ba{sub 0.75}Al{sub 11}O{sub 17.25} can be described by the formula Ba{sub 1{minus}x/4}Mg{sub 1{minus}x}Al{sub 10+x}O{sub 17+x/4} (0 {le} x {le} 1). The solid solution series BAM-II contains higher Mg concentrations. It can be expressed by the formula BA{sub 2}Mg{sub 6{minus}3y}Al{sub 28+2y}vacancies{sub y}O{sub 50} (O {le} y {le} 0.3). The Mg-rich end member of BAM-II is plotted exactly at the join between the defect-free end member of BAM-I and the stoichiometric Mg-Al-spinel. Thus it is concluded that the structure of BAM-II is a mixed-layer model containing both structure units.
Sponsoring Organization:
Deutsche Forschungsgemeinschaft, Bonn (Germany)
OSTI ID:
642170
Journal Information:
Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 136; ISSN 0022-4596; ISSN JSSCBI
Country of Publication:
United States
Language:
English