Corrosion protection of aluminum alloys with chromate-free inhibited conversion coatings in a tropical climate

• Y.A. Kuzenkov¹, C.D. Hong² and V.A. Karpov³

¹ A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31, 119071 Moscow, Russian Federation
² Joint Russian–Vietnamese Tropical Research and Technology Center, Hanoi, Socialist Republic of Vietnam
³ Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 119071, Moscow, Russian Federation

Abstract: Field corrosion tests in different regions of the world, including in tropical climates, show that aluminum alloys are subject to active pitting corrosion, so protection against it is an actual task. In the present work, we studied the effectiveness of protection of AMc, AMg3, D16, and V95 aluminum alloys with a chromate-free inhibited IFKhANAL-3 conversion coating (CC) under tropical climate for 3 years. It was shown that the chromate-free IFKhANAL-3 CC can protect D16 alloy for 9 months, and V95, AMg3 and AMc alloys for 12 months. To increase the duration of protection, these coatings were additionally treated with acrylate varnish and a hydrophobic layer of low molecular polytetrafluoroethylene (PTFE). In the case of acrylate varnish, this made it possible to reduce the number of pits on the samples after 3 years of tests. The layer of PTFE is subject to destruction due to exposure to ultraviolet light, but in its absence it allows to completely protect the aluminum alloys during the entire test period.

Keywords: aluminum alloys, conversion coating, pitting corrosion, corrosion inhibitors, atmospheric corrosion testing, tropical climate

Int. J. Corros. Scale Inhib., 2022, 11, no. 4, 1692-1702
doi: 10.17675/2305-6894-2022-11-4-18

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