Open AccessStructural study of Cu 2− x Se alloys produced by mechanical alloying
Author(s) -
Machado K. D.,
De Lima J. C.,
Grandi T. A.,
Campos C. E. M.,
Maurmann C. E.,
Gasperini A. A. M.,
Souza S. M.,
Pimenta A. F.
Publication year - 2004
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
eISSN - 1600-5740
pISSN - 0108-7681
DOI - 10.1107/s0108768104007475
Subject(s) - rietveld refinement , materials science , phase (matter) , crystallography , copper , ion , x ray crystallography , trigonal crystal system , diffraction , interstitial defect , analytical chemistry (journal) , crystal structure , metallurgy , chemistry , physics , organic chemistry , chromatography , optics , optoelectronics , doping
The crystalline structures of the superionic high‐temperature copper selenides Cu 2− x Se (0 < x < 0.25) produced using mechanical alloying were investigated using X‐ray diffraction (XRD). The measured XRD patterns showed the presence of peaks corresponding to the crystalline superionic high‐temperature α‐Cu 2 Se phase in the as‐milled sample, and its structural data were determined by means of a Rietveld refinement procedure. After heat treatment in argon at 473 K for 90 h, this phase transforms to the superionic high‐temperature α‐Cu 1.8 Se phase, whose structural data were also determined by Rietveld refinement. In this phase, a very low occupation of the trigonal 32( f ) sites (∼ 3%) by Cu ions is found. In order to explain the evolution of the phases in the samples, two possible mechanisms are suggested: (i) the high mobility of Cu ions in superionic phases and (ii) the important diffusive processes in the interfacial component of samples produced by mechanical alloying.