Preparação e caracterização do Sistema polifosfato misto contendo o ion Erbio

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

According to available published data, antimony polyphosphates have not attracted much attention from researchers. Currently polyphosphates of trivalent elements, including those of lanthanides, are widely employed in glasses suitable for light transmission within the region of telecommunication windows. In this case, the combination of antimony and rare earth polyphosphates cold be useful in order to prepare stable glasses with desirable chemical and physical properties. The present work deals with the investigation of erbium polyphosphate in its pure form and as part of a system containing antimony polyphosphate. The instrumental methods used were the following: chemical analysis, X-ray diffractometry, IR-spectroscopy, differential thermal analysis, differential thermogravimetric analysis and thermomechanical analysis. Static thermogravimetric technique was also used. Erbium polyphosphate Er(PO3)3 has been prepared using Er2O3, Sb2O3 and H3PO4 (85%) as starting materials and its physico-chemical properties studied. The study of binary system containing both antimony and erbium polyphosphate (molar interval 10%) showed that no solid solutions (neither of substution, nor intercalation) are formed in this system. Amorphous antimony polyphosphate acts exclusively as a neutral solid medium permitting the dilution of Er(PO3)3 present in the mixture to a desirable degree. The study of the system SbnErm(PO3)3 permitted the identification of a new polymorph modification of Er(PO3)3. On the basis of isostructural relationship with a plyphosphate belongs to lanthanide series it was indexed in the supposition of orthorhombic system, resulting in the parameters: a = 11.00A, b = 17.32A and c = 10.00A. No monoclinic distorsions were observed. Among the compositions comprising the binary system, the composition Sb0.7Er0.3(PO3)3 seems to be the most promising for the fabrication of polyphosphate glasses containing antimony and erbium. A methodology for obtaining transpatent samples stable at room humidity conditions was elaborated using the above composition. The study of thermomechanical properties of these glasses suggests that these possess polymeric stuctures characterized by plastic deformations. Water absorbtion characteristics are consistent with the Langmuir s model.

ASSUNTO(S)

vidros de fosfato rare earthy terras raras erbio polifostamisto polyphosphates polifosfatos fisica da materia condensada antimonio antymony

ACESSO AO ARTIGO

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