Contribution a l'etude du systeme cuivre-arsenic
1972; Elsevier BV; Volume: 7; Issue: 8 Linguagem: Inglês
10.1016/0025-5408(72)90128-6
ISSN1873-4227
Autores Tópico(s)Metallic Glasses and Amorphous Alloys
ResumoAbstract The phases in the Cu-As system have been studied and a new compound, Cu2As, has been synthesized. The e phase has a composition near to Cu6As. The homogeneity range of the β Cu3−xAs phase has been determined as a function of temperature (xmax = 0.35 at 700°C). From density measurements it can be concluded that the non-stoichiometry of the β Cu3−xAs phase arises from two mechanisms: the substitution of copper by arsenic and the formation of copper vacancies. The Cu2As phase has been obtained by selective wet oxidation starting from a phase with larger metal content. It crystallizes in the tetragonal system, “Fe2As” -type (z = 2, S.G. = P 4 nmm ): a = 3.788 ± 0.001 A and c = 5.942 ± 0.001 A . The atomic positions are: Cu (1) 0 0 0; 1 2 1 2 0; Cu (2) 0 1 2 0.303; 1 2 0 0.697; As 0 1 2 0.709; 1 2 0 0.291.
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