title: Structural study of Cu(2-x)Se alloys produced by mechanical alloying.
abstract: 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 alpha-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 alpha-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 ( approximately 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.
authors.affiliation: Depto de Física, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina 88040-900, Cx. P. 476, Brazil. kleber@fisica.ufsc.br
authors.forename: K D
authors.initials: KD
authors.lastname: Machado
authors.forename: J C
authors.initials: JC
authors.lastname: de Lima
authors.forename: T A
authors.initials: TA
authors.lastname: Grandi
authors.forename: C E M
authors.initials: CE
authors.lastname: Campos
authors.forename: C E
authors.initials: CE
authors.lastname: Maurmann
authors.forename: A A M
authors.initials: AA
authors.lastname: Gasperini
authors.forename: S M
authors.initials: SM
authors.lastname: Souza
authors.forename: A F
authors.initials: AF
authors.lastname: Pimenta
mesh_terms: D000497:Alloys / Q000138:chemical synthesis / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006358:Hot Temperature; D008968:Molecular Conformation; D033362:Powder Diffraction; D012643:Selenium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; D003300:Copper; D012643:Selenium