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Structural characterization of mullites synthesized by thermal decomposition of topaz

The structure of mullite obtained by thermal decomposition of topaz at 1340 °C and after additional thermal treatment at 1600 °C was characterized by 29Si and 27Al MAS NMR spectroscopy and x ray diffraction. No amorphous phase was detected by these techniques. The 29Si MAS NMR spectra of the mullite...

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Main Authors: Soares, Robson de Miranda, Sabioni, Antônio Claret Soares, Resck, Inês Sabioni, Falcomer, Viviane Aparecida Silva, Dias, José Alves, Silva, Naira Machado da, Menezes, Sônia Maria Cabral de, Costa, Geraldo Magela da
Format: Artigo
Language: English
Published: ABM, ABC, ABPol 2017
Subjects:
Mulita
Topázio
Raio X - difração
Online Access: http://repositorio.unb.br/handle/10482/27082
https://dx.doi.org/10.1590/S1516-14392007000100016
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spelling ir-10482-270822021-03-19T02:25:37Z Structural characterization of mullites synthesized by thermal decomposition of topaz Soares, Robson de Miranda Sabioni, Antônio Claret Soares Resck, Inês Sabioni Falcomer, Viviane Aparecida Silva Dias, José Alves Silva, Naira Machado da Menezes, Sônia Maria Cabral de Costa, Geraldo Magela da Mulita Topázio Raio X - difração The structure of mullite obtained by thermal decomposition of topaz at 1340 °C and after additional thermal treatment at 1600 °C was characterized by 29Si and 27Al MAS NMR spectroscopy and x ray diffraction. No amorphous phase was detected by these techniques. The 29Si MAS NMR spectra of the mullite samples showed four resonance peaks at -81, -86, -90 and -94 ppm. The peak at -81 ppm corresponded to silicon near oxygen vacancies in the mullite structure. The peak at 86 ppm was related to a sillimanite-type site and was the major contribution, ranging from 42 to 50%. The two other peaks, at -90.0 ppm and -94 ppm, were interpreted as resulting from rearrangements of the sillimanite-type site by the replacement of AlO4 by SiO4 tetrahedra16. The 27Al MAS NMR data of the two samples exhibited three different peaks, two of which were attributed to tetrahedral sites at 40 -45 and 63 -67 ppm, while the third was assigned to an octahedral site at about -6 ppm. The ratio of tetrahedral to octahedral aluminum sites was found to depend on the temperature applied during the preparation of the mullite and was higher at 1600 °C. 2017-12-07T04:48:30Z 2017-12-07T04:48:30Z 2007-03 Artigo SOARES, Robson de Miranda et al. Structural characterization of mullites synthesized by thermal decomposition of topaz. Materials Research, São Carlos, v. 10, n. 1, p. 75-78, jan./mar. 2007. DOI: https://doi.org/10.1590/S1516-14392007000100016. Disponível em: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392007000100016&lng=en&nrm=iso. Acesso em: 12 jan. 2021. http://repositorio.unb.br/handle/10482/27082 https://dx.doi.org/10.1590/S1516-14392007000100016 en Acesso Aberto Materials Research - All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License (CC BY NC 4.0). Fonte: https://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392007000100016&lng=en&tlng=en. Acesso em: 12 jan. 2021. application/pdf ABM, ABC, ABPol
institution REPOSITORIO UNB
collection REPOSITORIO UNB
language English
topic Mulita
Topázio
Raio X - difração
spellingShingle Mulita
Topázio
Raio X - difração
Soares, Robson de Miranda
Sabioni, Antônio Claret Soares
Resck, Inês Sabioni
Falcomer, Viviane Aparecida Silva
Dias, José Alves
Silva, Naira Machado da
Menezes, Sônia Maria Cabral de
Costa, Geraldo Magela da
Structural characterization of mullites synthesized by thermal decomposition of topaz
description The structure of mullite obtained by thermal decomposition of topaz at 1340 °C and after additional thermal treatment at 1600 °C was characterized by 29Si and 27Al MAS NMR spectroscopy and x ray diffraction. No amorphous phase was detected by these techniques. The 29Si MAS NMR spectra of the mullite samples showed four resonance peaks at -81, -86, -90 and -94 ppm. The peak at -81 ppm corresponded to silicon near oxygen vacancies in the mullite structure. The peak at 86 ppm was related to a sillimanite-type site and was the major contribution, ranging from 42 to 50%. The two other peaks, at -90.0 ppm and -94 ppm, were interpreted as resulting from rearrangements of the sillimanite-type site by the replacement of AlO4 by SiO4 tetrahedra16. The 27Al MAS NMR data of the two samples exhibited three different peaks, two of which were attributed to tetrahedral sites at 40 -45 and 63 -67 ppm, while the third was assigned to an octahedral site at about -6 ppm. The ratio of tetrahedral to octahedral aluminum sites was found to depend on the temperature applied during the preparation of the mullite and was higher at 1600 °C.
format Artigo
author Soares, Robson de Miranda
Sabioni, Antônio Claret Soares
Resck, Inês Sabioni
Falcomer, Viviane Aparecida Silva
Dias, José Alves
Silva, Naira Machado da
Menezes, Sônia Maria Cabral de
Costa, Geraldo Magela da
author_sort Soares, Robson de Miranda
title Structural characterization of mullites synthesized by thermal decomposition of topaz
title_short Structural characterization of mullites synthesized by thermal decomposition of topaz
title_full Structural characterization of mullites synthesized by thermal decomposition of topaz
title_fullStr Structural characterization of mullites synthesized by thermal decomposition of topaz
title_full_unstemmed Structural characterization of mullites synthesized by thermal decomposition of topaz
title_sort structural characterization of mullites synthesized by thermal decomposition of topaz
publisher ABM, ABC, ABPol
publishDate 2017
url http://repositorio.unb.br/handle/10482/27082
https://dx.doi.org/10.1590/S1516-14392007000100016
_version_ 1695119543141138432
score 13.657419

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