Studies of phase formation from the ZnO-CdO-V₂O₅ ternary system

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• 作者：R. Lozada-Morales ; L. Aquino-Meneses ; G. L贸pez-Calzada ; Ma.E. Zayas ; O. Zelaya-Angel ; J. Carmona-Rodriguez ; F. Rodriguez-Melgarejo ; S. Jim茅nez-S ; oval ; P. del Angel-Vicente ; E. Palacios-Gonzalez
• 关键词：Glasses ; Raman spectroscopy ; Crystalline solutions ; Diagram of compositions
• 刊名：Journal of Non-Crystalline Solids
• 出版年：15 February, 2014
• 年：2014
• 卷：386
• 期：Complete
• 页码：39-45
• 全文大小：1626 K

文摘

Trying different compositions to prepare the CdO-ZnO-V₂O₅ ternary system, two types of crystalline structures were found in the vanadate compounds. The interval of composition was separated in two regions. Region I was defined by the higher content of V₂O₅, meanwhile, region II was defined by the content of the kind of crystalline structures formed. In region I, vanadate compounds like: Cd_0.17V₂O₅, CdV₂O₆, ZnV₂O₆, and Cd₂V₂O₇ were found. Region II exhibited an unusual extended glass formation area, where all of the obtained samples were amorphous. The fabrication of the samples for each region was made by the conventional melt-quenching method. For the amorphous materials the nominal proportion in weight (wt. %) of the glass former (V₂O₅) ranged in the 40-10 wt.% interval, that is, it never reaches the largest proportion of the total weight. The modifier oxides CdO and ZnO, were between the 20-80 wt.% and 10-40 wt.% ranges, respectively.

The synthesized compounds in the regions I and II were identified through the X-ray diffraction and Raman spectroscopy techniques, additionally, by scanning electron microscopy, images of samples from region I were recorded and the sample M 70-20-10 was analyzed by high resolution transmission microscopy. Regarding the sketched boundary around the glass formation area, crystalline and semi-crystalline materials (depending on the proportions of the used reactants) like: Cd₂V₂O₇, Zn₂V₂O₇, Zn₃(VO₄)₂, ZnO; and combinations of them were identified. Within the glass formation area most of the glasses, depending on their chemical composition, presented a wide band whose maximum is centered between 860 and 840 cm^鈭?#xA0;1 in the Raman spectra.