Corrosion behavior of hydrotalcite coated AA 6061 alloy

• Autor(a) principal: FERNANDES, STELA M.
• Data de Publicação: 2016
• Outros Autores: CORREA, OLANDIR V., SOUZA, JOSE A., RAMANATHAN, LALGUDI V., ANTUNES, RENATO A., OLIVEIRA, MARA C. de, CONGRESSO BRASILEIRO DE CORROS??O, 34.; INTERNATIONAL CORROSION MEETING, 5th.; CONGRESO IBEROAMERICANO DE CORROSI??N Y PROTECCI??N, 10th.; CONCURSO DE FOTOGRAFIA DE CORROS??O E DEGRADA????O DE MATERIAIS, 19.; EXPOSI????O DE TECNOLOGIAS PARA PREVEN????O E CONTROLE DA CORROS??O, 34
• Tipo de documento: Artigo de conferência
• Título da fonte: Repositório Institucional do IPEN
• Texto Completo: http://repositorio.ipen.br/handle/123456789/26438
• topic: corrosion; coatings; aluminium; alloys; chemical preparation; x-ray diffraction; scanning electron microscopy; iear-1 reactor

Pitting corrosion of the aluminium cladding of spent research reactor (RR) fuel during wet storage is the main form of degradation and this could eventually lead to release of fissile material and contamination of storage facilities. Hence, the use of conversion coatings to protect spent Al-clad RR fuel during long term storage was proposed. Preliminary laboratory and field investigations carried out at IPEN in S??o Paulo, Brazil, revealed that cerium hydroxide coatings increased the corrosion resistance of Al alloys. These investigations were extended to include boehmite, hydrotalcite (HTC), cerium modified boehmite and cerium modified HTC coatings on Al alloy surfaces. This paper presents: (a) the preparation of hydrotalcite coatings from different baths followed by post-coating treatments; (b) the results of x-ray diffraction analysis and scanning electron microscopic studies of the HTC coatings; (c) the effect of HTC coating process variables such as temperature, duration of treatment and the duration of cerium modification on HTC morphology and electrochemical polarization behavior of HTC coated AA 6061 alloy in NaCl; (d) results of field tests in which uncoated and HTC coated AA 6061 coupons were exposed to the IEA-R1 reactor spent fuel basin for up to 5 months. The laboratory test specimens as well as the field test coupons coated with HTC from a high temperature bath followed by cerium modification were the most resistant to pitting.