Influence of cerium (IV) ions on the inorganic and organic phase for preparation of a siloxane-PMMA based film on tin plate substrate

• Autor(a) principal: Sarmento, V. H V [UNESP]
• Data de Publicação: 2008
• Outros Autores: Diniz, R. N. [UNESP], Benedetti, Assis Vicente [UNESP], Santilli, Celso Valentim [UNESP], Suegama, P. H., Aoki, I. V.
• Tipo de documento: Artigo de conferência
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://nace.confex.com/nace/ICC08/webprogram/Paper3795.html; http://hdl.handle.net/11449/70768
• topic: 3.5%Nacl; Corrosion phenomena; Corrosion problems; Corrosive agents; Dichromates; Dip coating techniques; Food canning; Food quality; Hybrid coating; Impedance measurement; Linear polarization; Modified film; Open circuits; Organic part; Organic phase; Physical barriers; Polarization curves; Protective properties; Sol-Gel processing; Cerium; Chromates; Corrosion prevention; Inorganic coatings; Polarization; Protective coatings; Sodium chloride; Sol-gel process; Tin; Tin plate; Tinning; Film preparation

Tinplate is one of the most widely used food canning materials, however, there are significant problems related to the use of tinplate cans, such as alterations in sensory features affecting food quality and corrosion phenomena of the canning material. To avoid corrosion problems different methods have been used for the passivation of tinplate such protective lacquers or different kinds of corrosion inhibitors (chromate and dichromate). However, chromates and dichromates are extremely harmful to the environment and can cause carcinogenic tumors to humans. An option, protective coatings obtained by the sol-gel process, act as a physical barrier, which isolates the surface of metal protecting from the corrosive agents. The aim of this work is to study the influence of addition of cerium (IV) ions in the inorganic and organic part of sol-gel processing in the formation of hybrid coatings based on siloxane-PMMA on tin plate. The coatings were obtained by dip-coating technique and evaluated by open circuit and impedance measurements, linear polarization and polarization curves obtained in 3.5% NaCl solution. The results have clearly shown the improvement on the protective properties of the Ce 4+ modified film when added into the organic phase, which can be due to the formation of a more uniform and densely reticulated siloxane-PMMA film. © 2009 by NACE International.