The devitrification kinetics of transparent silica glass prepared by gel-casting method
ABSTRACT The kinetics of the crystallization of cristobalite in the amorphous silica glass were studied for samples prepared by gel-casting and sintering in air. Avrami and rate equations were used to calculate the rate constants and the activation energy. The results showed that the crystallization...
| Autores: | , |
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| Tipo de documento: | artigo |
| Estado: | Versão publicada |
| Data de publicação: | 2019 |
| País: | Brasil |
| Recursos: | Matéria (Rio de Janeiro. Online) |
| Repositório: | Matéria (Rio de Janeiro. Online) |
| Idioma: | inglês |
| OAI Identifier: | oai:scielo:S1517-70762019000100344 |
| Acesso em linha: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1517-70762019000100344 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Devitrification Gel-Casting Silica Glass Cristobalite Crystallization |
| Resumo: | ABSTRACT The kinetics of the crystallization of cristobalite in the amorphous silica glass were studied for samples prepared by gel-casting and sintering in air. Avrami and rate equations were used to calculate the rate constants and the activation energy. The results showed that the crystallization obeys the first order and occurs mainly on the surface with activation energy of 543-546kJ/mol. The fewer amounts of OH-groups and the high amount of oxygen vacancies are expected to stand behind the increase in the activation energy as compared with that reported in literatures. |
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