DEMAT - Departamento de Engenharia de Materiais
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Article Shear bond strength of metal/ceramic interface after different surface treattments: an in vitro study(International Journal of Science Dentistry, 2012) Pereira, Sílvia Fontes do Amaral; Gouvêa, Cresus Vinícius Depes de; Carvalho, Waldimir; Nascimento, Rubens Maribondo do; Andrade, Simone Caixeta de; Buschinelli, José Augusto de AlmeidaThe aim of this in vitro study was to verify, by means of the shear test, the bonding strength of Wironia® light nickel-chrome alloy without beryllium, subjected to different surface treatments, to Vita VM13 and Noritake ceramics. Eighty cylindrical metal specimens were manufactured with aid from a steel matrix, measuring 4 mm in diameter by 4 mm height. The specimens were divided into eight groups (n=10), according to surface treatment applied to the metal alloy and type of ceramic tested. These were evaluated in accordance with shear strength criteria and, with the aid of optic microscopy the remained ceramic area adhered to metal after fracturing was evaluated. Specimens of G6 (manufactured with Noritake Ceramic treated with airborne particle abrasion-26.401 ± 11.637 MPa) presented the highest shear bond strength (p> 0,05), whereas the lowest values were recorded for G4 (the Vita Ceramic specimens bur treated -13,440 ± 7,766 MPa). G6 (19425,4 μm2) presented the biggest ceramic area adhered to metal (p> 0,05), whereas G4 (2310,2 μm2) presented the small area. In conclusion, G6 had the highest values for shear bond strength and metal adhere to surface, whereas G4 had the lowest values. Descriptor: Metal-ceramic restorations, nickel-chrome alloys, dental porcelain.Article NiO-CGO Composite for SOFC Anode: Synthesis and Characterization(Journal of Materials Science and Engineering, 2010) Cela, Beatriz; Macedo, Daniel Araújo de; Souza, Graziele Lopes de; Miranda, Auristela Carla de; Martinelli, Antonio Eduardo; Nascimento, Rubens Maribondo do; Paskocimas, Carlos AlbertoArticle Analysis of the Deformation of Composite Materials of Scrapes of Tire and Latex with Temperature Variation(David Publishing, 2012) Ford, Elmo Thiago Lins Cöuras; Nascimento, Rubens Maribondo do; Mendes, José Ubiragi de Lima; Marques, Antonio Torres; Pereira, Celeste Margarida CorreiaArticle Influência do teor de calcário no comportamento físico, mecânico e microestrutural de cerâmicas estruturais(Associação Brasileira de Cerâmica – ABCERAM, 2010) Nascimento, Rubens Maribondo do; Castro, R. J. S.; Martinelli, Antonio Eduardo; Soares, R. A. L.Article The effect of residence time on the tensile properties of superelastic and thermal activated Ni-Ti orthodontic wires(ABM, ABC, ABPol, 2011-08-05) Nascimento, Rubens Maribondo do; Britto, Kathia Maria Fosenca de; Spinelli, José Eduardo; Martinelli, Antonio EduardoArticle Estudo da potencialidade da aplicação de uma argila contaminada com calcário na produção de placas cerâmicas(Associação Brasileira de Cerâmica, 2012-12) Nascimento, Rubens Maribondo do; Soares, R. A. L.; Castro, R. J. S.In the city of Teresina area, capital of Piauí, Brazil, there is a lot of clay deposits red burning used in the production of structural ceramics, being the main reason for installing a ceramic center in the region. But many of these deposits are not being adequately exploited or simply abandoned because of contamination with limestone, which is the main undesirable contaminant for the ceramic producers pole of Teresina. Thus, this research aims to evaluate the capability of applying some clay with limestone in the production of these plates of red ceramic burning. A ceramic body used in the production of coating semiporous and a contaminated clay with limestone were characterized. The raw materials were burned in a separately industrial furnace and in combination on the proportions of 25%, 50% and 75% by weight of clay added with the industrial body. They were performed on specimens burned tests, linear shrinkage, water absorption and mechanical strength. The microstructure was assessed by mineralogical analysis. The results showed the potential use of contaminated clay with limestone mass of ceramic tileArticle Utilização de matérias primas argilosas no desenvolvimento de materiais cerâmicos especiais: parte I - caracterização(Revista Eletrônica de Materiais e Processos, 2012) Nascimento, Rubens Maribondo do; Alves Junior, Rubens; Dutra, Ricardo Peixoto Suassuna; Campos, Lizsandra Fernanda Araújo; Ferreira, H. S.; Lima, S. J. G.This paper proposes the development of a new type material with thermal and acoustic function, to be used by the construction industry. This material, formed by pressing, is composed of two layers: an inner layer with high porosity and an insulating function, and an outer layer, characterized by a low porosity, which has mechanical and aesthetic function. To develop this material was necessary to characterize different raw clay materials. Five different samples were collected from the coast of Paraiba which were characterized with the following tests: chemical analysis, particle size distributions, plasticity index and thermal analysis. In addition, the density, apparent porosity and shrinkage of the fired samples have been determined. The results show that the samples have different characteristics and suggests the sample 4 to form the outer material and the sample 1, due to high porosity and high temperature sintering to be used inside the materialArticle Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys(Associação Brasileira de Soldagem, 2013-12) Nascimento, Rubens Maribondo do; Pimenta, Jean Senise; Buschinelli, José de Almeida; Martinelli, Antonio Eduardo; Remmel, JosephUma cerâmica avançada é geralmente unida ao metal pelo processo de brasagem, porém o custo das ligas de adição ativas pode ser considerado uma limitação. A brasagem com uma liga de adição isenta de metal ativo para união dos componentes é uma tentativa de transpor esta desvantagem. A difusão de um metal ativo a partir do componente de titânio através do liga de adição fundida para o componente cerâmico produziu uma liga ativa in loco, promovendo a redução do óxido de zircônio e melhorando o molhamento na superfície cerâmica. Titânio não ligado foi unido a zircônia tetragonal (Y-TZP) e zircônia parcialmente estabilizada com magnésia (Mg-PSZ) em forno de alto vácuo (<3x10-5 mbar), usando ligas comerciais Ag-28Cu e Au-18Ni. Testes de detecção de vazamento de gás hélio foram realizados na interface cerâmica/metal à temperatura ambiente; amostras de juntas estanques foram analisadas por técnicas de análise microestrutural e análise por dispersão de raios-X na seção de união das juntas. Juntas estanques foram produzidas com a liga eutética Ag-Cu, formando-se uma camada intermetálica e uma camada escura de reação próxima à superfície cerâmica; a difusão de titânio foi eficiente para promover interações químicas entre os componentes. As juntas brasadas também foram ensaiadas com teste de flexão três-pontosArticle One-step synthesis of composite electrolytes of Eu-doped ceria and alkali metal carbonates(Elsevier, 2013-12-13) Nascimento, Rubens Maribondo do; Rajesh, Surendran; Macedo, Daniel Araújo de; Souza, Graziele Lopes de; Figueiredo, Filipe Miguel Henriques Lebre Ramos; Marques, Fernando M. B.Article Effect of cold plasma treatment on recycled polyethylene/kapok composites interface adhesion(Composite Interfaces, 2018-11-26) Feitor, Michele Cequeira; Macedo, Murilo José Pereira; Mattos, Adriano Lincoln Albuquerque; Costa, Thércio Henrique de Carvalho; Ito, Edson Noriyuki; Melo, José Daniel Diniz