18 documents found, page 1 of 2
Hybrid sol-gel coatings: Smart and green materials for corrosion mitigation
Figueira, R. B.; Fontinha, I. R.; Silva, C. J. R.; Pereira, E. V.Corrosion degradation of materials and metallic structures is one of the major issues that give rise to depreciation of assets, causing great financial outlays in their recovery and or prevention. Therefore, the development of active corrosion protection systems for metallic substrates is an issue of prime importance. The promising properties and wide application range of hybrid sol‐gel‐derived polymers have at...
Hybrid sol-gel coatings: smart and green materials for corrosion mitigation
Figueira, R. B.; Fontinha, I. R.; Silva, C. J. R.; Pereira, E. V.Corrosion degradation of materials and metallic structures is one of the major issues that give rise to depreciation of assets, causing great financial outlays in their recovery and or prevention. Therefore, the development of active corrosion protection systems for metallic substrates is an issue of prime importance. The promising properties and wide application range of hybrid sol-gel-derived polymers have at...
Influence of pH on the corrosion protection of epoxy-silica-zirconia sol-gel co...
Fontinha, I. R.; Salta, M. M.; Zheludkevich, M. L.; Ferreira, M. G. S.; Figueira, R. B.; Pereira, E. V.; Silva, C. J. R.Aluminium alloys of 6000 series can suffer severe corrosion in polluted (acidic) and/or marine environments and in contact with alkaline media like fresh cementitious materials. Therefore, architectural aluminium components are often coated, what requires its surface pre-treatment. Organic-inorganic hybrid (OIH) sol-gel coatings have been proposed as an effective, environmental compliant new pre-treatment for a...
Test of OIH gel composites with embedded corrosion inhibitors as corrosion prot...
Figueira, R. B.; Silva, C. J. R.; Pereira, E. V.Although the use of HDGS (hot-dip galvanized steel) in reinforced concrete structures shows improved corrosion resistance due to the presence of the zinc layer, when in contact with fresh concrete is strongly affected by the hydrogen evolution. Surface treatments such as chromate conversion layers are usually used to prevent this initial corrosion process which involves the use of reagents that have high impact...
Organic–inorganic hybrid sol–gel coatings for metal corrosion protection: a rev...
Figueira, R. B.; Silva, C. J. R.; Pereira, E. V.This paper is a review of the most recent and relevant achievements (from 2001 to 2013) on the development of organic–inorganic hybrid (OIH) coatings produced by sol–gel-derived methods to improve resistance to oxidation/corrosion of different metallic substrates and their alloys. This review is focused on the research of OIH coatings based on siloxanes using the sol–gel process conducted at an academic level a...
Alcohol-Aminosilicate Hybrid Coatings for Corrosion Protection of Galvanized St...
Figueira, R. B.; Silva, C. J. R.; Pereira, E. V.; Salta, M. M.Organic-inorganic hybrid (OIH) matrices were synthesized by sol-gel method and deposited on hot-dip galvanized steel (HDGS) using a dip-coating process. These OIHs, generally called amino-alcohol-silicates, were synthesized using a functionalized siloxane, 3-glycidoxypropyltrimethoxysilane, and five oligopolymers (Jeffamine) with different molecular weights: 230, 400, 600, 900 and 2000. Besides the five differe...
Corrosion Protection of Hot Dip Galvanized Steel in Mortar
Figueira, R. B.; Pereira, E. V.; Silva, C. J. R.; Salta, M. M.Corrosion of steel in concrete is one of the major causes of structure degradation, requiring expensive maintenance. The using of hot dip galvanized steel (HDGS) has been recognized as one effective measure to increase the service life of reinforced concrete structures in marine environmental. However, HDGS corrodes in contact with high alkaline environment of fresh concrete. Although this initial corrosion pro...
Electrochemical evaluation of hot-dip galvanized steel (HDGS) coated with organ...
Figueira, R. B.; Silva, C. J. R.; Pereira, E. V.; Salta, M. M.Organic-inorganic hybrid (OIH) sol-gel coatings based on ureasilicate gels present promising characteristics to be used as eco-friendly coatings for hot dip galvanized steel (HDGS), in contact with cementitious media, allowing to mitigate the harmful effects of an initial excessive reaction between cement pastes and the zinc. The long term performance of HDGS reinforcement coated with OIHs and embedded in concr...
Influence of the pH on the corrosion crotection of epoxy-silica-zirconia sol-se...
Fontinha, I. R.; Salta, M. M.; Zheludkevich, M.; Ferreira, M. G. S.; Figueira, R. B.; Pereira, E. V.; Silva, C. J. R.Aluminium alloys of 6000 series can suffer severe corrosion in polluted (acidic) and/or marine environments and in contact with alkaline media like fresh cementitious materials. Therefore, architectural aluminium components are often coated, what requires its surface pre-treatment. Organic-inorganic hybrid (OIH) sol-gel coatings have been proposed as an effective, environmental compliant new pre-treatment for a...
Strain induced enhanced ferromagnetic behavior in inhomogeneous low doped La0.9...
Das, S.; Amaral, J. S.; De, K.; Willinger, M.; Goncalves, J. N.; Roy, A.; Dhak, P.; Giri, S.; Majumder, S.; Silva, C. J. R.; Gomes, M. J. M.We report an unusual high-temperature ferromagnetic transition in bulk single-phase nanocrystalline La0.95Sr0.05MnO3+delta, achieved through localized strain and inhomogeneous Sr-doping. Magnetization measurements show a well defined transition at 290K and a broad one at similar to 150 K. HRTEM imaging reveals the strain on the highly crystalline nanometer sized grains and Sr-doping gradients, while oxygen homo...