dc.contributorPandolfelli, Victor Carlos
dc.contributorhttp://lattes.cnpq.br/7369376873984839
dc.contributorhttp://lattes.cnpq.br/6302194006113059
dc.creatorSouza, Tiago Marcolino de
dc.date.accessioned2012-11-29
dc.date.accessioned2016-06-02T19:10:12Z
dc.date.available2012-11-29
dc.date.available2016-06-02T19:10:12Z
dc.date.created2012-11-29
dc.date.created2016-06-02T19:10:12Z
dc.date.issued2012-09-12
dc.identifierSOUZA, Tiago Marcolino de. Elastic modulus as a tool for evaluating in situ transformations and for the development of refractory castables abstract. 2012. 296 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2012.
dc.identifierhttps://repositorio.ufscar.br/handle/ufscar/700
dc.description.abstractRefractory castables are multiphase materials usually exhibiting complex heterogeneous microstructures, which have their mechanical strength affected by chemical and structural changes. These microstructural changes directly affect the Young s modulus, as this property is strongly dependent on the chemical bonds, crystalline structure and flaws, such as porosity and cracks. For the Al2O3-MgO system, two transformations can be highlighted: the volumetric expansion associated with the magnesia hydration and the in situ spinel formation, both can play a role by increasing or decreasing the castable s embrittlement depending on the resulting expansion. Considering this aspect, the addition of MgO sources with different reactivity in refractory castables was evaluated during curing and drying steps. As a result, different routes for magnesia s sources addition to the castables, without the usual damage caused by MgO hydration, are presented in this work. The addition of acetic acid sped up the brucite precipitation, inducing the formation of a resilient structure able to inhibit the stresses generation. Additionally, the effect of mineralizing or densification compounds on spinel-forming castables and the microstructural evolution of refractory castables containing different MgO sources, colloidal binders or high-carbon content were assessed during the thermal treatment by hot Young s modulus measurements using the resonance bar technique. The attained results highlight the technique s broad feature and accuracy for the development of refractory materials. The MgF2 and magnesium borate addition sped up the spinel formation, whereas TiO2 led to lower expansion values and greater rigidity at high temperatures, all of them as promising alternatives to master the castable s microstructure design. For the nano-bonded castables, the sintering additive addition further enhanced the Young s modulus resulting in high-performance refractories. Additionally, the elastic modulus measurements were able to evaluate the antioxidants effect in high-carbon containing castables and to identify the mechanisms of crack healing (during heating) and opening (during cooling).
dc.publisherUniversidade Federal de São Carlos
dc.publisherBR
dc.publisherUFSCar
dc.publisherPrograma de Pós-Graduação em Ciência e Engenharia de Materiais - PPGCEM
dc.rightsAcesso Aberto
dc.subjectCerâmica
dc.subjectElasticidade
dc.subjectConcretos refratários
dc.subjectÓxido de magnésio
dc.titleMódulo elástico como ferramenta para o acompanhamento de transformações in situ e desenvolvimento de concretos refratários
dc.typeTesis


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