Corrosion and tribocorrosion behaviour of Al-Si-Cu-Mg alloy and its composites reinforced with B4C particles in 0.05M NaCl solution

The corrosion behaviour of metal matrix composites (MMCs) is strictly linked with the presence of heterogeneities such as reinforcement phase, microcrevices, porosity, secondary phase precipitates, and interaction products. Most of the literature related to corrosion behaviour of aluminium matrix composites (AMCs) is focused on SiC reinforced AMCs. On the other hand, there is very limited information available in the literature related to the tribocorrosion behaviour of AMCs. Therefore, the present work aims to investigate corrosion and tribocorrosion behaviour of Al-Si-Cu-Mg alloy matrix composites reinforced with B4C particulates. Corrosion behaviour of 15 and 19% (vol) B4C reinforced Al-Si-Cu-Mg matrix composites and the base alloy was investigated in 0.05M NaCl solution by performing immersion tests and potentiodynamic polarisation tests. Tribocorrosion behaviour of Al-Si-Cu-Mg alloy and its composites were also investigated in 0.05M NaCl solution. The tests were carried out against alumina ball using a reciprocating ball-on-plate tribometer. Electrochemical measurements were performed before, during, and after the sliding tests together with the recording of the tangential force. Results suggest that particle addition did not affect significantly the tendency of corrosion of Al-Si-Cu-Mg alloy without mechanical interactions. During the tribocorrosion tests, the counter material was found to slide mainly on the B4C particles, which protected the matrix alloy from severe wear damage. Furthermore, the wear debris were accumulated on the worn surfaces and entrapped between the reinforcing particles. Therefore, the tendency of corrosion and the corrosion rate decreased in Al-Si-Cu-Mg matrix B4C reinforced composites during the sliding in 0.05M NaCl solution. © 2013 Elsevier B.V.

Si-based thin film coating on Y-TZP: Influence of deposition parameters on adhesion of resin cement

This study evaluated the influence of deposition parameters for Si-based thin films using magnetron sputtering for coating zirconia and subsequent adhesion of resin cement. Zirconia ceramic blocks were randomly divided into 8 groups and specimens were either ground finished and polished or conditioned using air-abrasion with alumina particles coated with silica. In the remaining groups, the polished specimens were coated with Si-based film coating with argon/oxygen magnetron discharge at 8:1 or 20:1 flux. In one group, Si-based film coating was performed on air-abraded surfaces. After application of bonding agent, resin cement was bonded. Profilometry, goniometry, Energy Dispersive X-ray Spectroscopy and Rutherford Backscattering Spectroscopy analysis were performed on the conditioned zirconia surfaces. Adhesion of resin cement to zirconia was tested using shear bond test and debonded surfaces were examined using Scanning Electron Microscopy. Si-based film coating applied on air-abraded rough zirconia surfaces increased the adhesion of the resin cement (22.78 ± 5.2 MPa) compared to those of other methods (0-14.62 MPa) (p = 0.05). Mixed type of failures were more frequent in Si film coated groups on either polished or air-abraded groups. Si-based thin films increased wettability compared to the control group but did not change the roughness, considering the parameters evaluated. Deposition parameters of Si-based thin film and after application of air-abrasion influenced the initial adhesion of resin cement to zirconia. © 2013 Elsevier B.V. All rights reserved.

O teatro, a educação e a experiência de si

Pós-graduação em Artes - IA

Hélio Oiticica: antropófago de si mesmo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Monitoramento de hosts em redes tcp/ip sobre base georreferenciada com métricas de qualidade

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese de filmes híbridos de SI/PMMA-DR1 por processo sol-gel e caracterização

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Espectroscopia de impedância em vidros 22Na2O·8CaO·65SiO2·5MO2 (M = Si, Ti, Ge, Zr, Sn, Ce) sem e com troca iônica Ag+ Na+

Pós-graduação em Física - IGCE

ALBA-TCP: uma cultura de integração regional alternativa para a América Latina?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Machado de Assis leitor de si mesmo: um estudo a respeito da reescrita de alguns contos machadianos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O desenvolvimento psíquico na idade de transição e a formação da individualidade para-si: aportes teóricos para a educação escolar de adolescentes

Pós-graduação em Educação Escolar - FCLAR

Os modos contemporâneos de gestão do espaço urbano e a invenção de si

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cuidado de si e a educação matemática: perspectivas, reflexões e práticas de atores sociais (1925-1945)

Pós-graduação em Educação Matemática - IGCE

A construção social da personalidade de adolescentes expostos ao bullying escolar e os processos de “resiliência em-si”: uma análise histórico-cultural

Pós-graduação em Educação - FCT

As aventuras do corpo: dos modos de subjetivação às memórias de si em revista impressa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A construção poética de si mesmo: Manoel de Barros e a autobiografia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)