Hybrid Sol-Gel Coatings Doped with Non-Toxic Corrosion Inhibitors for Corrosion Protection on AZ61 Magnesium Alloy

Abstract

Physiological human fluid is a natural corrosive environment and can lead to serious corrosion and mechanical damages to light Mg–Al alloys used in prosthetics for biomedical applications. In this work, organic–inorganic hybrid coatings doped with various environmentally friendly and non-toxic corrosion inhibitors have been prepared by the sol-gel process for the corrosion protection of AZ61 magnesium alloys. Effectiveness has been evaluated by pH measurements, optical microscopy, and SEM during a standard corrosion test in a Hanks’ Balanced Salt Solution. The results showed that the addition of an inhibitor to the sol-gel coating can improve significantly the corrosion performance, being an excellent barrier for the L-cysteine-doped hybrid sol-gel films. The incorporation of TiO2 nanoparticles, 2-Aminopyridine and quinine organic molecules slowed down the corrosion rate of the Mg–Al alloy. Graphene oxide seemed to have the same response to corrosion as the hybrid sol-gel coating without inhibitors.

Advances in the Modification of Silane-Based Sol-Gel Coating to Improve the Corrosion Resistance of Magnesium Alloys

“…The corrosion inhibitor-loaded sol-gel coating is mainly achieved by incorporating appropriate inhibitors in the sol preparation process [ 59 , 60 ]. These corrosion inhibitors are stored in the prepared sol-gel coating.…”

An overview on the use of corrosion inhibitors for the corrosion control of Mg and its alloys in diverse media

“…The natural corrosive environment of physiological human fluid can cause substantial corrosion and mechanical damage to light MgeAl alloys used in biomedical prosthesis. Rodrguez-Alonso et al [2] investigated the effectiveness of hybrid sol-gel coatings with and without corrosion inhibitors, such as L-cysteine, TiO 2 nanoparticles, 2aminopyridine, quinine, dimetyl glyoxime, and graphene oxide sheet, for the protection of AZ61 Mg alloy in Hanks' Balance Salt solution for 14 days immersion. The results demonstrated that adding an inhibitor to the sol-gel coating can increase corrosion performance greatly, and that it is an effective barrier for L-cysteine-doped hybrid sol-gel films.…”

Eco-Friendly Sol–Gel Coatings with Organic Corrosion Inhibitors for Lightweight AZ61 Alloy

“…The recent transition to organic inhibitors is motivated by their enhanced inhibitory capacity, attributed to the presence of multiple heteroatoms and double bonds. This shift reflects a commitment to advancing corrosion protection methods in a more sustainable and environmentally conscious direction [ 13 , 14 , 15 , 16 , 17 , 18 ].…”