Navegando por Autor "Manhabosco, Sara Matte"
Agora exibindo 1 - 7 de 7
Resultados por página
Opções de Ordenação
Item Comparison between hydroxyapatite/soapstone and hydroxyapatite/ reduced graphene oxide composite coatings : synthesis and property improvement.(2021) Nicomedes, Daniel Nilson Nunes; Mota, Laureana Moreira; Vasconcellos, Rebecca; Medrado, Nathanael Vieira; Oliveira, Michelle de; Alvarenga, Érika Lorena Fonseca Costa de; Juste, Karyne Ramos de Campos; Righi, Ariete; Manhabosco, Sara Matte; Silva, Guilherme Jorge Brigolini; Araújo, Fernando Gabriel da Silva; Oliveira, Alan Barros de; Batista, Ronaldo Junio Campos; Soares, Jaqueline dos Santos; Manhabosco, Taíse MatteEconomic viability and eco-friendliness are important characteristics that make implants available to the pop- ulation in a sustainable way. In this work, we evaluate the performance of a low-cost, widely available, and eco- friendly material (talc from soapstone) relative to reduced graphene oxide as reinforcement to brittle hy- droxyapatite coatings. We employ a low-cost and straightforward technique, electrodeposition, to deposit the composite coatings on the titanium substrate. Corrosion, wear, and biocompatibility tests indicate that the reduced graphene oxide can be effectively replaced by talc without reducing the mechanical, anticorrosion, and biocompatible composite coatings properties. Our results indicate that talc from soapstone is a promising ma- terial for biomedical applications.Item Corrosion behaviour of galvanized steel studied by electrochemical microprobes applied on low-angle cross sections.(2019) Manhabosco, Sara Matte; Manhabosco, Taíse Matte; Geoffroy, Nicolas; Vignal, Vincent; Dick, Luís Frederico PinheiroThe combined use of the microcapillary cell (MEC) and scanning vibrating electrode technique (SVET) and lowangle cross sections was employed to elucidate the role of each coating region on the protection of the cut-edge corrosion of galvanized steels. Different compounds are involved in the blocking action of the corrosion products: Zincite (ZnO) on the steel substrate, hydrozincite (Zn5(OH)6(CO3)2) at the coating/steel interface, and Simonkolleite (Zn5(OH)8Cl2) and ZnO on the different coating regions in different proportions. The coating surface is also active at the initial stage and during long-term protection and thus, must be considered in experimental simulation of the cut-edge corrosion.Item Determination of current maps by svet of hot-dip galvanized steel under simultaneous straining.(2015) Manhabosco, Sara Matte; Batista, Ronaldo Junio Campos; Silva, Sabrina Neves da; Dick, Luís Frederico PinheiroA new experimental procedure was used to analyse the corrosion behaviour of hot-dip Zn coated steel based on the association of the scanning vibrating electrode technique (SVET) and uniaxial tensile strain applied up to 3.1% in 0.01 M NaCl solutions without release of the elastic strain during the test. The nucleation of localized corrosion sites on the coating occurs at very low strain values around the yield point and the maximum current densities increase continuously with the increase of the applied strain. The nucleation of localized corrosion on the Zn surface was favoured by the rupture of the passive film in contact with the solution by the action of slip steps and fine intergranular cracks, rather than by the exposure of the steel substrate. Straining of the Zn coating immersed in the solution was comparatively a much more aggressive condition than straining the sample in air before the corrosion tests.Item Electrochemical atomic layer epitaxy deposition of ultrathin SnTe films.(2019) Manhabosco, Taíse Matte; Aloni, Shaul; Kuykendall, Tevye R.; Manhabosco, Sara Matte; Batista, Ana Bárbara; Soares, Jaqueline dos Santos; Barboza, Ana Paula Moreira; Oliveira, Alan Barros de; Batista, Ronaldo Junio Campos; Urban, Jeffrey J.Tin telluride (SnTe) ultrathin films were deposited electrochemically on polycrystalline and monocrystalline gold substrates using the electrochemical atomic layer epitaxy (ECALE) method. The electrochemical behaviors of Sn and Te were studied systematically by means of cyclic voltammetry. Cyclic voltammetry curves for Sn displayed a broad peak in the region between -0.15 V and -0.35 V, which was related to the under-potential deposition (UPD), while the curves for Te displayed a peak at 0.3 V for Te UPD. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM) were employed for the characterization of the ultrathin SnTe films. XRD and Raman spectroscopy confirmed the deposition of a single SnTe phase, while SEM revealed that the deposits were composed of nanocrystallites.Item Eletrodeposição de revestimentos compósitos de hidroxiapatita/óxido de grafeno sobre substrato de liga de magnésio.(2021) Carneiro, Larissa da Silva; Manhabosco, Taíse Matte; Soares, Jaqueline dos Santos; Manhabosco, Sara Matte; Manhabosco, Taíse Matte; Barboza, Ana Paula Moreira; Alvarenga, Érika Lorena Fonseca Costa deA elevada taxa de envelhecimento populacional demanda uma particular atenção devido ao aumento significativo de doenças que acometem o sistema esquelético, sendo necessário intervenção médica no reparo e reconstrução de estruturas ósseas. Diante desse cenário, a aplicação do Magnésio e suas ligas vêm sendo estudada como implantes metálicos biodegradáveis, apesar de sua alta taxa de corrosão em condições fisiológicas. Com o intuito de minimizar este problema, revestimentos de hidroxiapatita (Ca10(PO4)6(OH)2) vêm sendo amplamente empregados devido sua biocompatibilidade. Neste trabalho, objetiva-se o aumento da resistência à corrosão e ao desgaste de liga de magnésio AZ31 pela eletrodeposição pulsada de revestimentos de hidroxiapatita com a incorporação de óxido de grafeno nas seguintes concentrações de 0,1 g/L, 0,01 g/L e 0,001 g/L. Para a análise dos revestimentos realizou-se a microscopia de varredura eletrônica, espectroscopia Raman, difração de raios X, ensaio de polarização potenciodinâmica e ensaio de desgaste. As imagens ao microscópio eletrônico de varredura revelaram que os revestimentos de hidroxiapatita pura depositados por 40 minutos sobre substrato de liga de magnésio com tratamento térmico alcalino apresentam morfologia mais adequada ao se comparar com os revestimentos depositados por tempo de 30 e 60 minutos sobre os substratos tratados em meio ácido e meio térmico alcalino. Os resultados de espectroscopia Raman dos revestimentos apresentam o pico de maior intensidade em 960cm-1 , típica da hidroxiapatita e as bandas D e G que são características do óxido de grafeno. A difratometria de raios X confirmou a estrutura cristalina da hidroxiapatita. Dentre os revestimentos compósitos com diferentes concentrações de óxido de grafeno, verificou-se que a incorporação de 0,1 g/L desse material conduz a uma morfologia com menor ocorrência de trincas e melhor interligação da matriz de hidroxiapatita, além de um aumento na resistência à corrosão em comparação ao substrato puro e uma redução no dano de desgaste (largura das trilhas de desgaste) de 10%. Porém, os resultados da polarização potenciodinâmica dos revestimentos de hidroxiapatita pura evidenciaram uma superior resistência à corrosão ao se comparar com os revestimentos compósitos. Dessa forma, este trabalho apresenta uma contribuição no estudo de revestimentos de ligas metálicas para aplicações biomédicas, uma vez que apresenta revestimentos cerâmicos e compósitos que podem ser utilizados para melhorar a resistência à corrosão e desgaste de ligas de magnésio.Item Soapstone reinforced hydroxyapatite coatings for biomedical applications.(2020) Mota, Laureana Moreira; Nicomedes, Daniel Nilson; Barboza, Ana Paula Moreira; Ramos, Sérgio Luís Lima de Moraes; Vasconcelos, Rebecca Schirmer de Souza; Medrado, Nathanael Vieira; Alvarenga, Érika Lorena Fonseca Costa de; Machado, Giovanna; Juste, Karyne Ramos de Campos; Vasconcelos, Cláudia Karina Barbosa de; Righi, Ariete; Manhabosco, Sara Matte; Resende, Rodrigo Ribeiro; Batista, Ronaldo Junio Campos; Soares, Jaqueline dos Santos; Manhabosco, Taíse MatteMechanical resistant bioactive materials are of high interest for biomedical applications. In this work, we address the improvement in mechanical properties of HA coatings by the addition of a cheap and widely available secondary phase material, the talc from soapstone. The composites hydroxyapatite/talc (HA/talc) were successfully obtained by pulsed electrodeposition and characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy, corrosion and wear resistance and biocompatibility tests. We found that the addition of talc greatly improves the mechanical properties of coatings (i. e., wear track and friction coefficient in wear tests were significantly diminished) without diminishing corrosion resistance and biocompatibility. Alamar Blue® tests, alkaline phosphatase activity, and collagen production indicate that the biocomposites are biocompatible and talc itself induce bone maturation.Item Structural, optical, and magnetic evaluation of Co-, Ni-, and Mn-modified multiferroic BiFeO3 ceramics.(2021) Sales, Joel Neto Bispo de; Silva, Rafael Tomaz da; Lara, Luciano Roni Silva; Ramos, Sérgio L. L. M.; Soares, Jaqueline dos Santos; Soares, Thiago André Salgueiro; Machado, Giovanna; Manhabosco, Sara Matte; Oliveira, Alan Barros de; Carvalho, Hugo Bonette de; Batista, Ronaldo Junio Campos; Stumpf, Humberto Osório; Manhabosco, Taíse MatteCo-, Ni-, and Mn-doped BiFeO3 (BFO) ceramics were synthesized herein through a solid-state reaction. All doped BFO samples exhibit visible-light response, and the Co- and Ni-doped BFO samples present enhanced ferro-magnetic order at room temperature. All doped samples show secondary phases in minor quantities. Optical spectra reveal two absorptions bands, indicating multiple electron transitions for BFO and its secondary phases. M − H hysteresis loops suggest enhanced ferromagnetism in the Co- and Ni-doped BFO samples because of magnetic spinel CFP and NFO phases, respectively, whereas changes in oxygen vacancies and Fe–O–Fe bond angle play minor roles in the ferromagnetic behavior.