The Role of the Hydrolysis and Zirconium Concentration on the Structure and Anticorrosion Performances of a Hybrid Silicate Sol-Gel Coating

Authors

Maikki Cullen, Technological University Dublin, School of Chemical and Pharmaceutical Sciences, Dublin, IrelandFollow
Mary O’Sullivan, Technological University Dublin, Centre for Research in Engineering Surface Technology (CREST), Dublin, Ireland
Aditya Madhan Kumar, Indian Institute of Technology (Indian School of Mines), Dhanbad, Department of Chemical Engineering, Dhanbad, India
Ahmad A. Sorour, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
Brendan Duffy, Technological University DublinFollow
Mohamed Oubaha, Technological University DublinFollow

Document Type

Article

Rights

Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence

Disciplines

1.4 CHEMICAL SCIENCES

Publication Details

https://link.springer.com/article/10.1007/s10971-018-4657-3

Abstract

In sol-gel chemistry, hydrolysis is the key step in the formation of the reactive hydroxide groups that are responsible for the formation of inorganic networks via the occurrence of condensation reactions. Though previous studies have investigated the effect of the hydrolysis conditions on the structure of organically modified silicates (ormosils), no study, to our knowledge, has investigated this variable on the structure of hybrid materials prepared by combinations of an ormosil and a transition metal (TM). Here, we propose to investigate this effect in a hybrid material composed of 3-trimethoxysilylpropylmethacrylate and a zirconium complex. To also highlight the effects of the precursor’s concentrations on the hydrolysis and condensation reactions of the hybrid materials, their relative content was altered along with the hydrolysis degree. The anticorrosion barrier properties were identified by characterisation of coatings deposited on AA2024-T3 substrates and correlation between the structure and the anticorrosion properties of the coatings were performed based on results obtained from structural characterisations (DLS, FTIR, 29Si-NMR, DSC, AFM and SEM) and corrosion testing (EIS and NSS). It is demonstrated that competition in the formation of siloxane and Si-O-Zr bonds takes place and can be controlled by the degree of hydrolysis and the concentration of the zirconium complex. This effect was found to dramatically alter the morphology of the coatings and their subsequent anticorrosion performances. At shortterm exposure times, it is found that the most condensed materials exhibited a higher corrosion resistance while over longer periods the performances were found to level. This article highlighted the critical impact of the hydrolysis degree and zirconium concentration on the connectivity of hybrid sol-gel coatings and the impact this has on corrosion performances.

DOI

https://doi.org/10.1007/s10971-018-4657-3

Recommended Citation

Cullen, M., O'Sullivan, M. & Kumar, A.M. (2018). The role of the hydrolysis and zirconium concentration on the structure and anticorrosion performances of a hybrid silicate sol-gel coating. Journal of Sol-Gel Science and Technology, vol. 86, no. 3, pg. 553-567 doi:10.1007/s10971-018-4657-3