Avrami exponent of crystallization in tellurite glasses

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Data

2011-11-01

Autores

Sidel, S. M. [UNESP]
Santos, F. A. [UNESP]
Gordo, V. O. [UNESP]
Idalgo, E. [UNESP]
Monteiro, A. A. [UNESP]
Moraes, João Carlos Silos [UNESP]
Yukimitu, K. [UNESP]

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Editor

Springer

Resumo

Nucleation process and crystal growth for three samples of the (20-x)Li(2)O-80TeO(2)-xWO(3) glass system were studied using X-ray diffraction and differential scanning calorimetry techniques. X-ray diffraction data confirmed the amorphous characteristic of the as-quenched samples and indicated the growth of crystalline phases formed due to the thermal treatment for annealed samples. These results reveal the presence of three distinct gamma-TeO(2), alpha-TeO(2) and alpha-Li(2)Te(2)O(5) crystalline phases in the TL sample, and two distinct alpha-TeO(2) and gamma-TeO(2) crystalline phases in the TLW5 and TLW10 samples. The activation energy and the Avrami exponent were determined from DSC measurements. The activation energy values X-ray diffraction data of the TLW10 glass sample suggest that gamma-TeO(2) phase occur before the alpha-TeO(2). The results obtained for the Avrami exponent point to that the nucleation process is volumetric and that the crystal growth is two or three-dimensional.

Descrição

Palavras-chave

Tellurite glasses, Nucleation, Crystallization, Activation energy, XRD, DSC

Como citar

Journal of Thermal Analysis and Calorimetry. Dordrecht: Springer, v. 106, n. 2, p. 613-618, 2011.