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Study of Ordering in High‐Quartz Solid Solutions by Substitutions Affecting Superlattice Reflections
Author(s) -
RAY SATYABRATA
Publication year - 1973
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/j.1151-2916.1973.tb12348.x
Subject(s) - superlattice , quartz , solid solution , crystallography , interstitial defect , materials science , period (music) , condensed matter physics , chemistry , physics , metallurgy , doping , acoustics
Ordering of the interstitial and network atoms in stuffed high‐quartz solid‐solution ( ss ) phases was studied by correlating suitable substitutions in the structure with the resultant changes in the superlattice reflections arising from these phases. In an MgO·Al 2 O 3 ·3SiO 2 high‐quartz ss , the special ordering of the interstitial Mg atoms, which produces satellite reflections around superlattice positions, was disturbed by replacement of ∼20 mol% of the MgO by Li 2 O or ZnO. The interstitial atoms were further disordered by larger substitutions. The streaked superlattice reflections arising from an Li 2 O·Al 2 O 3 ·2SiO 2 high‐quartz ss disappeared on replacement of ∼40 mol% of the Li 2 O by MgO. This result implies that the interstitial Li atoms are ordered and were disordered by the substitution. The superlattice reflections were much intensified when ∼25 mol% of the SiO 2 was replaced by GeO 2 . However, these reflections were intensified to a lesser degree when presumably both SiO 2 and Al 2 O 3 were partially replaced by GeO 2 and Ga 2 O 3 , respectively. These observations strongly suggest an ordering of the network Si and Al atoms, which, together with the ordering of the interstitial Li atoms, contributed to the original streaked superlattice reflections.