Nucleação transiente e estacionária em dissilicato de lítio
Autor(a) principal: | |
---|---|
Data de Publicação: | 2018 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/11363 |
Resumo: | Glasses and supercooled liquids tend to crystallize below the melting temperature. Crystallization is a phase transformation where the atomic structure ceases to be non-crystalline and becomes periodic. The focus of this work is on the process of emergence of one or more crystalline regions in a super-cooled liquid, known as crystal nucleation. The Classical Theory of Nucleation (CNT) is one of the theoretical bases that explain this process. Experimental results and previous analyzes show that the CNT is sufficient to describe the crystal nucleation rate as a function of temperature, but only for temperatures above the maximum nucleation temperature. Another issue is the way experimental data are obtained, generally using the double-treatment technique. This technique is known to overestimate the intrinsic induction time of nucleation. The objective of this project is to investigate these two CNT problems in a rigorous way to seek a resolution for both. Our results showed that the time of the nucleation treatment has a considerable influence on the values obtained for both the stationary nucleation rate and the induction time. Therefore, experiments performed for too short times may be the cause for the disagreement (theory / experiment) found below the maximum nucleation temperature. In this work, using longer nucleation times, the obtained nucleation rates were higher than those reported in the literature and the detachment between theoretical prediction and experimental values occurred at lower temperatures. |
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Serra, André Hofmeister MartinsZanotto, Edgar Dutrahttp://lattes.cnpq.br/1055167132036400Cassar, Daniel Robertohttp://lattes.cnpq.br/1717397276752482http://lattes.cnpq.br/6543196529138903f30681f2-35ad-4786-87cd-3b928bab635c2019-05-03T19:45:23Z2019-05-03T19:45:23Z2018-05-29SERRA, André Hofmeister Martins. Nucleação transiente e estacionária em dissilicato de lítio. 2018. Dissertação (Mestrado em Ciência e Engenharia de Materiais) – Universidade Federal de São Carlos, São Carlos, 2018. Disponível em: https://repositorio.ufscar.br/handle/ufscar/11363.https://repositorio.ufscar.br/handle/ufscar/11363Glasses and supercooled liquids tend to crystallize below the melting temperature. Crystallization is a phase transformation where the atomic structure ceases to be non-crystalline and becomes periodic. The focus of this work is on the process of emergence of one or more crystalline regions in a super-cooled liquid, known as crystal nucleation. The Classical Theory of Nucleation (CNT) is one of the theoretical bases that explain this process. Experimental results and previous analyzes show that the CNT is sufficient to describe the crystal nucleation rate as a function of temperature, but only for temperatures above the maximum nucleation temperature. Another issue is the way experimental data are obtained, generally using the double-treatment technique. This technique is known to overestimate the intrinsic induction time of nucleation. The objective of this project is to investigate these two CNT problems in a rigorous way to seek a resolution for both. Our results showed that the time of the nucleation treatment has a considerable influence on the values obtained for both the stationary nucleation rate and the induction time. Therefore, experiments performed for too short times may be the cause for the disagreement (theory / experiment) found below the maximum nucleation temperature. In this work, using longer nucleation times, the obtained nucleation rates were higher than those reported in the literature and the detachment between theoretical prediction and experimental values occurred at lower temperatures.Vidros e líquidos super-resfriados tendem a se cristalizar abaixo da temperatura de fusão. A cristalização é uma transformação de fase onde a estrutura atômica deixa de ser não-cristalina e passa a ser periódica. O foco deste trabalho é o processo de surgimento de uma ou mais regiões cristalinas num líquido super-resfriado, conhecido como nucleação de cristais. A Teoria Clássica da Nucleação (CNT) é uma das bases teóricas que explicam este processo. Resultados experimentais e análises anteriores mostram que a CNT é suficiente para descrever a taxa de nucleação de cristais em função da temperatura, mas apenas para temperaturas acima da temperatura de máxima nucleação. Outra problemática é a forma como os dados experimentais de nucleação são obtidos, em geral utilizando-se da técnica de tratamento duplo. Esta técnica é conhecida por superestimar o tempo de indução intrínseco da nucleação. O objetivo deste projeto é investigar estes dois problemas da CNT de forma rigorosa a fim de buscar uma resolução para ambos. Os nossos resultados mostraram que o tempo de tratamento de nucleação tem influência significativa nos valores obtidos, tanto para a taxa de nucleação estacionária como para o tempo de indução. Portanto, experimentos efetuados por tempos demasiadamente curtos podem ser a causa para o desacordo (teoria / experimento) verificado abaixo da temperatura de máxima nucleação. Neste trabalho, usando tempos de nucleação mais longos, as taxas de nucleação obtidas foram maiores do que as reportadas na literatura e o descolamento entre a previsão teórica e os valores experimentais ocorreu em temperaturas mais baixas.Não recebi financiamentoporUniversidade Federal de São CarlosCâmpus São CarlosPrograma de Pós-Graduação em Ciência e Engenharia de Materiais - PPGCEMUFSCarTaxa de nucleaçãoCristalizaçãoDissilicato de lítioNucleação transienteNucleação estacionáriaNucleation rateCristallizationLithium disilicateTransient nucleationStationary nucleationENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA::MATERIAIS NAO METALICOSNucleação transiente e estacionária em dissilicato de lítioTransient and stationary nucleation in vitreous lithium disilicateinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisOnline6006006cfabc63-f3c2-48d1-ba85-c4d9edda486binfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINALAndré Hofmeister Martins Serra - Dissertação.pdfAndré Hofmeister Martins Serra - Dissertação.pdfapplication/pdf1770532https://repositorio.ufscar.br/bitstream/ufscar/11363/1/Andr%c3%a9%20Hofmeister%20Martins%20Serra%20-%20Disserta%c3%a7%c3%a3o.pdfccc9c2afa581a5dce4f3183d7bd4b08eMD51LICENSElicense.txtlicense.txttext/plain; charset=utf-81957https://repositorio.ufscar.br/bitstream/ufscar/11363/3/license.txtae0398b6f8b235e40ad82cba6c50031dMD53TEXTAndré Hofmeister Martins Serra - Dissertação.pdf.txtAndré Hofmeister Martins Serra - Dissertação.pdf.txtExtracted texttext/plain135578https://repositorio.ufscar.br/bitstream/ufscar/11363/4/Andr%c3%a9%20Hofmeister%20Martins%20Serra%20-%20Disserta%c3%a7%c3%a3o.pdf.txtffccc84c6f4f18fdedd27b534ca759f1MD54THUMBNAILAndré Hofmeister Martins Serra - Dissertação.pdf.jpgAndré Hofmeister Martins Serra - Dissertação.pdf.jpgIM Thumbnailimage/jpeg5970https://repositorio.ufscar.br/bitstream/ufscar/11363/5/Andr%c3%a9%20Hofmeister%20Martins%20Serra%20-%20Disserta%c3%a7%c3%a3o.pdf.jpg6881571bb161abdac7432b1cd029b710MD55ufscar/113632023-09-18 18:31:22.255oai:repositorio.ufscar.br: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Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:31:22Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Nucleação transiente e estacionária em dissilicato de lítio |
dc.title.alternative.eng.fl_str_mv |
Transient and stationary nucleation in vitreous lithium disilicate |
title |
Nucleação transiente e estacionária em dissilicato de lítio |
spellingShingle |
Nucleação transiente e estacionária em dissilicato de lítio Serra, André Hofmeister Martins Taxa de nucleação Cristalização Dissilicato de lítio Nucleação transiente Nucleação estacionária Nucleation rate Cristallization Lithium disilicate Transient nucleation Stationary nucleation ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA::MATERIAIS NAO METALICOS |
title_short |
Nucleação transiente e estacionária em dissilicato de lítio |
title_full |
Nucleação transiente e estacionária em dissilicato de lítio |
title_fullStr |
Nucleação transiente e estacionária em dissilicato de lítio |
title_full_unstemmed |
Nucleação transiente e estacionária em dissilicato de lítio |
title_sort |
Nucleação transiente e estacionária em dissilicato de lítio |
author |
Serra, André Hofmeister Martins |
author_facet |
Serra, André Hofmeister Martins |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/6543196529138903 |
dc.contributor.author.fl_str_mv |
Serra, André Hofmeister Martins |
dc.contributor.advisor1.fl_str_mv |
Zanotto, Edgar Dutra |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/1055167132036400 |
dc.contributor.advisor-co1.fl_str_mv |
Cassar, Daniel Roberto |
dc.contributor.advisor-co1Lattes.fl_str_mv |
http://lattes.cnpq.br/1717397276752482 |
dc.contributor.authorID.fl_str_mv |
f30681f2-35ad-4786-87cd-3b928bab635c |
contributor_str_mv |
Zanotto, Edgar Dutra Cassar, Daniel Roberto |
dc.subject.por.fl_str_mv |
Taxa de nucleação Cristalização Dissilicato de lítio Nucleação transiente Nucleação estacionária |
topic |
Taxa de nucleação Cristalização Dissilicato de lítio Nucleação transiente Nucleação estacionária Nucleation rate Cristallization Lithium disilicate Transient nucleation Stationary nucleation ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA::MATERIAIS NAO METALICOS |
dc.subject.eng.fl_str_mv |
Nucleation rate Cristallization Lithium disilicate Transient nucleation Stationary nucleation |
dc.subject.cnpq.fl_str_mv |
ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA::MATERIAIS NAO METALICOS |
description |
Glasses and supercooled liquids tend to crystallize below the melting temperature. Crystallization is a phase transformation where the atomic structure ceases to be non-crystalline and becomes periodic. The focus of this work is on the process of emergence of one or more crystalline regions in a super-cooled liquid, known as crystal nucleation. The Classical Theory of Nucleation (CNT) is one of the theoretical bases that explain this process. Experimental results and previous analyzes show that the CNT is sufficient to describe the crystal nucleation rate as a function of temperature, but only for temperatures above the maximum nucleation temperature. Another issue is the way experimental data are obtained, generally using the double-treatment technique. This technique is known to overestimate the intrinsic induction time of nucleation. The objective of this project is to investigate these two CNT problems in a rigorous way to seek a resolution for both. Our results showed that the time of the nucleation treatment has a considerable influence on the values obtained for both the stationary nucleation rate and the induction time. Therefore, experiments performed for too short times may be the cause for the disagreement (theory / experiment) found below the maximum nucleation temperature. In this work, using longer nucleation times, the obtained nucleation rates were higher than those reported in the literature and the detachment between theoretical prediction and experimental values occurred at lower temperatures. |
publishDate |
2018 |
dc.date.issued.fl_str_mv |
2018-05-29 |
dc.date.accessioned.fl_str_mv |
2019-05-03T19:45:23Z |
dc.date.available.fl_str_mv |
2019-05-03T19:45:23Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
SERRA, André Hofmeister Martins. Nucleação transiente e estacionária em dissilicato de lítio. 2018. Dissertação (Mestrado em Ciência e Engenharia de Materiais) – Universidade Federal de São Carlos, São Carlos, 2018. Disponível em: https://repositorio.ufscar.br/handle/ufscar/11363. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/11363 |
identifier_str_mv |
SERRA, André Hofmeister Martins. Nucleação transiente e estacionária em dissilicato de lítio. 2018. Dissertação (Mestrado em Ciência e Engenharia de Materiais) – Universidade Federal de São Carlos, São Carlos, 2018. Disponível em: https://repositorio.ufscar.br/handle/ufscar/11363. |
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https://repositorio.ufscar.br/handle/ufscar/11363 |
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openAccess |
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Universidade Federal de São Carlos Câmpus São Carlos |
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Programa de Pós-Graduação em Ciência e Engenharia de Materiais - PPGCEM |
dc.publisher.initials.fl_str_mv |
UFSCar |
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Universidade Federal de São Carlos Câmpus São Carlos |
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