Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminate
Autor(a) principal: | |
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Data de Publicação: | 2021 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10773/36900 |
Resumo: | Calcium hexaluminate (CA6) is an intrinsically densification-resistant material, therefore, its porous structures are key materials for applications as high-temperature thermal insulators. This article reports on the combination of calcined alumina and calcium aluminate cement (CAC) in castable aqueous suspensions for the in situ production of porous CA6. The CAC content (10–34 vol%) and the curing conditions ensure structural integrity prior to sintering and maximize the development of hydrated phases. Changes in physical properties, crystalline phases, and microstructure were investigated after isothermal treatments (120–1500 °C), and three sequential porogenic events were observed. The hydration of CAC preserved the water-derived pores (up to 120 °C), and the dehydroxylation of CAC hydrates (250–700 °C) generated inter-particles pores. Moreover, the in situ expansive formation of CA2 and CA6 (900–1500 °C) hindered densification and generated intra-particle pores. Such events differed from those observed with other CaO sources, and resulted in significantly higher pores content and lower thermal conductivity. |
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7160 |
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Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminateCalcium hexaluminateAluminaCalcium aluminate cementPorous ceramicsCalcium hexaluminate (CA6) is an intrinsically densification-resistant material, therefore, its porous structures are key materials for applications as high-temperature thermal insulators. This article reports on the combination of calcined alumina and calcium aluminate cement (CAC) in castable aqueous suspensions for the in situ production of porous CA6. The CAC content (10–34 vol%) and the curing conditions ensure structural integrity prior to sintering and maximize the development of hydrated phases. Changes in physical properties, crystalline phases, and microstructure were investigated after isothermal treatments (120–1500 °C), and three sequential porogenic events were observed. The hydration of CAC preserved the water-derived pores (up to 120 °C), and the dehydroxylation of CAC hydrates (250–700 °C) generated inter-particles pores. Moreover, the in situ expansive formation of CA2 and CA6 (900–1500 °C) hindered densification and generated intra-particle pores. Such events differed from those observed with other CaO sources, and resulted in significantly higher pores content and lower thermal conductivity.Elsevier2023-06-01T00:00:00Z2021-06-01T00:00:00Z2021-06-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10773/36900eng0272-884210.1016/j.ceramint.2021.02.066Salomão, RafaelKawamura, Mirian A.Emilio, Ana B.V.Sakihama, JoséSegadães, Ana M.info:eu-repo/semantics/embargoedAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T12:11:07Zoai:ria.ua.pt:10773/36900Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:07:33.682293Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminate |
title |
Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminate |
spellingShingle |
Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminate Salomão, Rafael Calcium hexaluminate Alumina Calcium aluminate cement Porous ceramics |
title_short |
Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminate |
title_full |
Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminate |
title_fullStr |
Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminate |
title_full_unstemmed |
Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminate |
title_sort |
Calcium aluminate cement in castable alumina: from hydrate bonding to the in situ formation of calcium hexaluminate |
author |
Salomão, Rafael |
author_facet |
Salomão, Rafael Kawamura, Mirian A. Emilio, Ana B.V. Sakihama, José Segadães, Ana M. |
author_role |
author |
author2 |
Kawamura, Mirian A. Emilio, Ana B.V. Sakihama, José Segadães, Ana M. |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Salomão, Rafael Kawamura, Mirian A. Emilio, Ana B.V. Sakihama, José Segadães, Ana M. |
dc.subject.por.fl_str_mv |
Calcium hexaluminate Alumina Calcium aluminate cement Porous ceramics |
topic |
Calcium hexaluminate Alumina Calcium aluminate cement Porous ceramics |
description |
Calcium hexaluminate (CA6) is an intrinsically densification-resistant material, therefore, its porous structures are key materials for applications as high-temperature thermal insulators. This article reports on the combination of calcined alumina and calcium aluminate cement (CAC) in castable aqueous suspensions for the in situ production of porous CA6. The CAC content (10–34 vol%) and the curing conditions ensure structural integrity prior to sintering and maximize the development of hydrated phases. Changes in physical properties, crystalline phases, and microstructure were investigated after isothermal treatments (120–1500 °C), and three sequential porogenic events were observed. The hydration of CAC preserved the water-derived pores (up to 120 °C), and the dehydroxylation of CAC hydrates (250–700 °C) generated inter-particles pores. Moreover, the in situ expansive formation of CA2 and CA6 (900–1500 °C) hindered densification and generated intra-particle pores. Such events differed from those observed with other CaO sources, and resulted in significantly higher pores content and lower thermal conductivity. |
publishDate |
2021 |
dc.date.none.fl_str_mv |
2021-06-01T00:00:00Z 2021-06-01 2023-06-01T00:00:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10773/36900 |
url |
http://hdl.handle.net/10773/36900 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
0272-8842 10.1016/j.ceramint.2021.02.066 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/embargoedAccess |
eu_rights_str_mv |
embargoedAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Elsevier |
publisher.none.fl_str_mv |
Elsevier |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
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1799137730440986624 |