The influence of heat treatment of inorganic conversion coatings produced by sol-gel dip coating on the anticorrosive properties of alumina films deposited on steel substrate - Part II: silica/boehmite or boehmite/silica multilayered conversion coatings

SURFACE & COATINGS TECHNOLOGY

卷:386

Article

Castro Braga, Antonio Vitor¹  Baptista do Lago, Dalva Cristina¹  Pimenta, Andre Rocha²  de Senna, Lilian Ferreira¹ 

[1] Univ Estado Rio De Janeiro, Dept Analyt Chem, Lab Electrochem & Corros, Rua Sao Francisco Xavier,524,PHLC,Sala 427, BR-20559013 Rio De Janeiro, RJ, Brazil

[2] Sci & Technol Rio de Janeiro Campus Paracambi, Fed Inst Educ, Lab Comp Instrumentat & Simulat, Rua Sebastiao de Lacerda,S-N Fabr, BR-26600000 Paracambi, RJ, Brazil

关键词: Alumina;    Dip coating;    Sol-gel;    Multilayered conversion coating;    Heat treatment;   

DOI  :  10.1016/j.surfcoat.2020.125500

来源: Elsevier

【 摘 要 】

Following on the results presented in the first part of this study, the focus of attention now shifts to the influence of different deposition sequences and heat treatment temperatures on the production of multilayered conversion coatings of silica and boehmite on 1020 carbon steel, aiming the improvement of the anticorrosive performance of alumina coatings in a saline medium. Thus, conversion coatings composed by different deposition sequences of two xerogel films (boehmite/silica and silica/boehmite films), were evaluated by SEM and XRD after heat treatment. After covering these multilayered conversion coatings containing silica and boehmite with alumina film, the systems were characterized by electrochemical impedance spectroscopy in NaCl 0.5 mol L-1 solution. Both kinds of multilayered conversion coatings improved the anticorrosive performance of the alumina film in the aggressive medium, independent of the coating arrangement and the heat treatment temperature used. Moreover, this parameter affected the composition and morphology of both kinds of conversion coatings, directly influencing on the anticorrosive properties of the final coating systems. Among all of the systems studied in the present work, the one produced using silica/boehmite deposition sequence and heat-treated at 600 degrees C showed the most significant improvement in the corrosion protection of steel in a saline medium.

【 授权许可】

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