Hydrophobic and anticorrosion properties of thin phosphonate–siloxane films formed on a laser textured zinc surface

• G.V. Redkina, A.S. Sergienko and Yu.I. Kuznetsov

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31, 119071 Moscow, Russian Federation

Abstract: The effect of preliminary laser treatment of zinc surface and its subsequent heating on the anticorrosion and hydrophobic properties of the layers formed in solutions of sodium dodecylphosphonate (SDDP) and trialkoxysilanes (TAS), i.e. vinyltrimethoxysilane (VTMS) or n-octyltriethoxysilane (OTES), has been studied. The polymodal roughness of the zinc surface resulting from laser and heat treatment allows one to achieve its superhydrophobization upon layer-by-layer passivation with SDDP and TAS as well as to increase the protective properties of the thin films formed by them. Apparently, the surface morphology obtained by such treatment provides better adhesion of the first phosphonate layer. In combination with a strong siloxane network in the top layer, this determines the high protective and hydrophobic properties of the coatings and their stability over time. The most effective is layer-by-layer passivation of zinc in SDDP and OTES solutions with preliminary laser texturing of the surface, which allows one to obtain resistant coatings with high protective and hydrophobic properties in a humid atmosphere. In the presence of OTES, which is more hydrophobic than VTMS and has a relatively long alkyl, a stable highly ordered siloxane layer is formed on the zinc surface, which is capable of blocking existing defects in the film formed by the chemisorbed alkylphosphonate.

Keywords: zinc, passivation, corrosion inhibitor, alkylphosphonates, trialkoxysilanes, laser treatment, superhydrophobicity

Int. J. Corros. Scale Inhib., 2020, 9, no. 4, 1550-1563 PDF (696 K)
doi: 10.17675/2305-6894-2020-9-4-23

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