On the crystallization of gel-derived albite (NaAlSi3O8): the most stable oxide glass

Autor(es)

Siqueira, Renato Luiz ; Peitl, Oscar ; Zanotto, Edgar Dutra

• Tipo de documento: Artigo Científico
• Fonte: Journal of Sol-Gel Science and Technology; v. 80, n. 3, p. 619-625, DEC 2016.
• Citações Web of Science: 2

Resumo

Some glass-forming oxides, such as unseeded B2O3 and albite (NaAlSi3O8), exhibit outstandingly high resistance to devitrification and have never been crystallized at ambient pressure. For instance, a classical study reported that an albite glass produced by melting was held at 1025 A degrees C (close to the maximum growth rate predicted by a theoretical model) for 5 years without crystallizing. In this study, we tested the crystallization behavior of gel-derived albite glasses synthesized through two distinct and original routes and compared them with a melt-quenched sample because sol-gel glasses normally crystallize much faster than isochemical melt-derived glasses. Not only the melt-derived glass but also one of the gel samples (which contained much more OH- than its melted counterpart) remained amorphous in a differential scanning calorimetry experiment and after 12 h of heat treatment at 1000 and 1030 A degrees C. The other gel-derived material contained residual carbon partially crystallized during the same thermal treatment at 1000 and 1030 A degrees C. Therefore, in the absence of a suitable nucleating agent, crystallization does not occur, even in gel-derived albite glass with a high OH- content. {[}GRAPHICS] . (AU)

• Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs