Hybrid Sol-Gel Coatings: Smart and Green Materials for Corrosion Mitigation

Abstract

Corrosion degradation of materials and metallic structures is one of the major issues that give rise to depreciation of assets, causing great financial outlays in their recovery and or prevention. Therefore, the development of active corrosion protection systems for metallic substrates is an issue of prime importance. The promising properties and wide application range of hybrid sol-gel-derived polymers have attracted significant attention over recent decades. The combination of organic polymers and inorganic materials in a single phase provides exceptional possibilities to tailor electrical, optical, anticorrosive, and mechanical properties for diverse applications. This unlimited design concept has led to the development of hybrid coatings for several applications, such as transparent plastics, glasses, and metals to prevent these substrates from permeation, mechanical abrasion, and corrosion, or even for decorative functions. Nevertheless, the development of new hybrid products requires a basic understanding of the fundamental chemistry, as well as of the parameters that influence the processing techniques, which will briefly be discussed. Additionally, this review will also summarize and discuss the most promising sol-gel coatings for corrosion protection of steel, aluminium, and their alloys conducted at an academic level.

Influence of silica nanoparticles on corrosion resistance of sol-gel based coatings on mild steel

“…It was found that increasing the organic content (via the glyc id yl group of the GPTMS) in the sol-gel based matrix formulation helped to improve the adhesion of the coating to the substrate as well as provide more uniform and thicker coatings, which is in agreement with other studies [32,33]. Thus, a TES40/GPTMS molar ratio of 1:1.8 was selected as the preferred matrix formulation due to its uniformity, its lower susceptibility to cracking and its enhanced thickness.…”

Corrosion Protection Systems and Fatigue Corrosion in Offshore Wind Structures: Current Status and Future Perspectives

“…Therefore, future trends for commercial OWS coatings are predicted to match current research interests such as low cost, pollution-free, self-healing products that are easy to synthesize and apply. The coatings should be effective in corrosion control for long service lives in a wide range of environments [108]. It is clear that studies on the behaviour of innovative coating systems need to be performed in OWSs since scarce information was found by the authors of this paper.…”

“…In the last few decades, several types of organic-based coatings have been developed [85], including anti-fouling paints [70,[86][87][88][89][90][91][92][93][94], composites and nano-coatings [94][95][96], self-healing coatings [97][98][99][100][101][102][103][104][105][106][107], and hybrid sol-gel materials [98,[108][109][110][111][112][113][114][115][116][117][118][119][120][121] among others. However, as far as the authors' knowledge, very few studies were performed on OWSs using self-healing and hybrid sol-gel coatings.…”

“…Coatings with pre-emptive healing abilities will be one of the main targets in the coating industry [97,100,102,103,106,107,[219][220][221][222][223][224][225][226][227][228][229][230][231]. Combined systems (multilayers) that associate different layers with distinct functions will be improved and/or developed in order to achieve the most efficient protection possible against corrosion [34,37,108,117]. These coatings may be comprised of metal-rich coatings, containing zinc or magnesium particles or other inhibitor particles.…”

Particle Characterisation and Depletion of Li2CO3 Inhibitor in a Polyurethane Coating

“…Many new inhibitor systems have been the subject of extensive research, including rare earths [1][2][3][4][5][6][7][8][9][10][11][12][13][14], vanadates [15,16], organic compounds [17][18][19][20][21][22][23], sacrificial particles or functional properties in coatings [24][25][26][27][28], double-layered hydroxides containing inhibitors [29][30][31][32][33][34][35][36][37][38][39][40][41] and, in many cases, combinations of these. The search for alternatives is probably most intense for aerospace applications, where chromate inhibitors have been the mainstay of corrosion prevention for many decades.…”