Preparation and characterization of environmentally friendly sol-gel hybrid coatings for corrosion protection of AA2024

Lakshmi, RV and Balaraju, JN and Mohan, AVN and Basu, Bharathibai J (2013) Preparation and characterization of environmentally friendly sol-gel hybrid coatings for corrosion protection of AA2024. In: CORCON 2013, 2013-09-30, New Delhi.

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    Abstract

    Sol-gel hybrid coatings were developed as potential replacement for the environmentally hazardous chromate conversion coatings for AA2024 aluminum alloy. The sol was prepared by acid catalysis of a mixture of glycidoxypropyltrimethoxysilane (GPTMS) and Zirconium (IV) tetrapropoxide (TPOZ) and doped with an inorganic corrosion inhibitor like cerium salt. It was applied on to AA2024 substrate by spray-coating technique. Coated coupons were characterized by Field emission scanning electron microscopy (FESEM) and micrographs of the as-prepared sol-gel coatings showed a pore-free and crack-free surface. Corrosion resistance of the sol-gel coatings in 3.5% NaCl solution was evaluated by potentiodynamic polarization measurements. Coatings have also been evaluated by continuous salt spray exposure. The effect of cerium salt concentration on the corrosion protection efficiency of the sol-gel hybrid coatings was studied. The GZC sol-gel coating doped with optimized cerium inhibitor were applied on (10 x 3 inch2) size samples and subjected to salt spray test. The developed GZC sol-gel coatings were comparable to CCC and offered excellent protection to the AA2024 substrate. Chemical composition of the coated substrates after salt spray test indicated increased concentration of cerium indicating migration of cerium to the exposed area resulting in corrosion protection of the surface.

    Item Type: Conference or Workshop Item (Paper)
    Uncontrolled Keywords: Corrosion protection;Sol-gel hybrid coatings;Potentiodynamic polarization measurements
    Subjects: AERONAUTICS > Avionics & Aircraft Instrumentation
    Division/Department: Surface Engineering Division, Surface Engineering Division, Other, Surface Engineering Division
    Depositing User: Mrs Manoranjitha M D
    Date Deposited: 29 Jul 2015 10:40
    Last Modified: 14 Dec 2015 15:53
    URI: http://nal-ir.nal.res.in/id/eprint/12269

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