Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation

Abstract

Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

Hybrid Sol–gel Coatings for Corrosion Mitigation: A Critical Review

“…The sol-gel method offers several advantages when compared to traditional synthesis processes [1,36,[125][126][127]; namely, the ease of fabrication and flexibility of the process, the large number of precursor reagents commercially available with tuned functional groups and the low environmental impact. Furthermore, sol-gel also allows for excellent control of the stoichiometry of the precursor; and the incorporation of different components that introduce complementary functions to the material (Figure 2), such as UV protection [128][129][130], anti-fouling [131,132], anti-reflection [133,134], moisture resistance [135], corrosion protection [15,16,31,38,[136][137][138] and detection of biological components [88,139]-proteins [140] and enzymes [92,141], antibodies [142,143], DNA [95,144,145], polysaccharides [146,147], etc. This feature allows one to obtain, in a simple way, smart and multifunctional materials.…”

Prospects of Low-Pressure Cold Spray for Superhydrophobic Coatings

“…This powder form and the degree of dispersity originates from the application of base catalyst, ammonia [49,50] while the repeatable architecture of cauliflower-like sheathed SiO 2 -F particles-the individual steps of synthesis. The macroscopic analysis ensured that the FOTS-covered SiO 2 spheres (Figure 1a,b) are characterized by the high level of size and shape uniformity in submicron scale which is typical for sol-gel synthesized products [21,39,[46][47][48][49][50][51]. Furthermore, the size distribution analysis ( Figure 1c) illustrates average SiO 2 -F spheres diameter of 670 nm with the shape deviation ±50 nm which is rather common for silica formed in the Stöber process [22,47,48,59].…”

“…As a rule, with the unique water-repelling feature of these surfaces, their use is associated with the ability to reduce wear of metal surfaces due to corrosion in the aquatic environment [16][17][18][19]. Superhydrophobic surfaces can minimize the interaction between metal substrates and corrosive substances and provide better anti-corrosion properties by reduction of contact time with water [16][17][18]20,21]. Often it facilitates self-cleaning potential taking advantage of low water adhesion [16,18,19,[22][23][24].…”

“…First of all, the functionality of feedstock powder may be easily achieved on the sol-gel route, because carefully planned synthesis may provide the set of new, programmable features. Unlike the utilization of ready-made powders with properties ensured by the manufacturer, simple SiO 2 -chemistry design [21,30,39,[46][47][48][49][50][51][52] enables for adding functionalities with hydrophobicity as a leading example in this paper. Secondly, the hydrophobic surface must have two important parameters: adequate roughness and low free surface energy [6].…”

Novel pyrazole derivatives as inhibitors of stainless steel in 2.0M H2SO4 media: Electrochemical Study

“…Several methods of corrosion protection have been considered so far by several authors 12,13 . These methods can be classified between those that modify the potential of the electrode on the metal surface or those that modify the nature of the metal itself.…”