1,720,986 research outputs found
Valutazione della rugosità e del comportamento elettrochimico del titanio in ambiente biologico
No full textA multifactor approach to evaluate the sealing of “smooth-wall” containers for food packaging
No full textThe Improvement of Durability of Biodegradable Magnesium Alloy by Using Bio-Inspired Coating
No full textApplication of EIS to In Situ Characterization of Hydrothermal Sealing of Anodized Aluminum Alloys: Comparison between Hexavalent Chromium-Based Sealing, Hot Water Sealing and Cerium-Based Sealing
Full text linkChromic acid anodizing has been used for almost a century to enhance corrosion protection of aerospace alloys. For some applications,hydrothermal sealing in hexavalent chromium-containing solution is required to enhance further the corrosion resistance but, due toenvironmental concerns, the use of hexavalent chromium must be discontinued. Good progress has been made to replace chromatesduring anodizing but comparatively less effort has focused on the sealing process. In this work, for the first time, electrochemicalimpedance spectroscopy (EIS) has been used to characterize in-situ the sealing processes occurring during hot water sealing,sodium chromate sealing and cerium sealing. The results suggest that the processes occurring during sodium chromate sealing aresignificantly different compared to hot water and cerium sealing. In particular, during chromate sealing, the porous skeleton issignificantly attacked, suggesting that the anticorrosion performance is likely to arise from the residuals of chromate rather than fromthe improvement of the barrier properties. In contrast, during hot water sealing, little attack occurs on the porous skeleton, and theimproved corrosion protection is due to the enhanced barrier effect. During cerium sealing, precipitation of cerium products occurs,providing an inhibitor reservoir, and little, if any, attack occurs on the pre-existing oxide
Enhancement of photooxidative and corrosion resistance of epoxy/graphene water-based coatings on metallic substrate
No full textGraphene nanoplatelets (GNPs)dispersed in low quantity in a waterborne epoxy resin enhance the coating anticorrosive properties and strongly contrast its photooxidative degradation. The study of the photooxidative behaviour monitored until 600 h, highlights a very relevant result from an applicative point of view. A low percentage of GNPs (1% by weight)determines a reduction in the increase of the carbonyl groups amount of 78 wt% compared to the unfilled sample. Furthermore, a low quantity of GNPs incorporated in the organic coating reveals a significant enhancement in the corrosion resistance, as demonstrated by electrochemical analysis. Results show that the greater the amount of GNPs the slower the absorption. Equivalent electrical circuits, by means of the “two-parallel-layer” model, are used to interpret the electrochemical behaviour, considering the complex nature of the waterborne and inhibitors free coating. A new promising strategy is foreseen for enhancing the performance of the coating service life
Corrosion behaviour of AA2024-T3 anodized in tartaric sulphuric acid and sealed in environmentally friendly solutions
No full textStudio di un caso di failure di contenitori in alluminio nel settore del packaging alimentare
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