A Review of Modern Assessment Methods for Metal and Metal-Oxide Based Primers for Substrate Corrosion Protection

Abstract

Pigmented coatings developed for the corrosion protection of engineering alloys have been successful in the field of corrosion control, and thus are ubiquitous in application. Supporting this success are an array of methods to diagnostically assess these systems and measure their state of degradation. These methods assist the development of next generation coatings, in-service evaluation, and post-mortem analysis of performance. This review comprehensively explores these modern assessment methods, used to screen candidate corrosion prevention pigments, assess pigment protection efficiency, quantify overall pigment effectiveness, and/or predict coating service lifetime. Coating service life assessment is conducted based on the class of coating considered, as categorized by (1) chemical inhibition, (2) galvanic protection, (3) high impedance ion barrier, or a combination of these protection mechanisms. Exciting new in-situ and operando methods are growing in use to enable high fidelity measurement of chemical inhibitor release and deposition, such as micro and in-situ Raman spectroscopy and inductively coupled plasma atomic emission spectrometry (ICP-AES), to name a few. In the galvanic protection coating class, service life and the state of coating performance are now being quantified through methods such as galvanostatic pulse and accelerated cycle testing. Galvanic throwing power is assessed by scanning vibrating electrode technique (SVET), multi-electrode array (MEA), and scanning kelvin probe (SKP). The performance of high impedance ion barrier coatings has traditionally been understood through use of electrochemical impedance spectroscopy (EIS) and equivalent circuit modeling, which have been applied to all coating classes. Finite element analysis (FEA) models the combined effects of coating resistance, water layer thickness, and pigment potential on galvanic coupling and/or inhibitor species release as well. The development of effective corrosion prevention pigments and the in-service evaluation of their efficiency/effectiveness demands a broad collection of techniques. These methods now include new advances in thermodynamic modeling via chemical stability diagrams to McMahon et al. Assessment Methods for Metal-Rich Primer Performance assess pigment function in specific conditions, in-situ pH measurement, as well as energy dispersive (EDS) and x-ray photoelectron spectroscopic (XPS) analyses to determine elemental distribution and corrosion product formation. These techniques and more are explored in this review to document the state-of-the-art in the field.

Transforming Damage into Benefit: Corrosion Engineering Enabled Electrocatalysts for Water Splitting

“…[ 34,35 ] Accordingly, there are intensive effects being carried out to prevent metal corrosion, such as pigmented coating, electrochemical protection, and adding corrosion inhibitors. [ 36,37 ] However, the harmful corrosion can be applied to prepare the serviceable electrocatalysts, leading to the result of “transforming damage into benefit.” Actually, corrosion is a spontaneous oxidation–reduction reaction process occurred in different micro regions on the surface of metals, which generally produces the corrosion layers of rusts. [ 38 ] These waste rusts may be employed as functional nanomaterials for electrochemical reactions.…”

A Materials Science Perspective of Midstream Challenges in the Utilization of Heavy Crude Oil

“…Alternatives to zinc and chromate coatings include polymers, metal oxides, and self-assembled molecular monolayers. − Substantial research has focused on the development of nanocomposite thin-film coatings that incorporate nanoparticles in various base polymer matrices to activate multiple modes of corrosion inhibition. For instance, we have designed hybrid nanocomposite coatings that incorporate multiwalled carbon nanotubes or graphene with a polyetherimide (PEI) matrix to offer synergistic corrosion inhibition to low alloy steels through an “active–passive” mechanism .…”

“…At low graphene concentrations, graphene fillers induce greatly increased tortuosity of ion diffusion pathways, enabling excellent corrosion protection of underlying aluminum alloys, whereas at high concentrations, graphene flakes form a percolative network and initiate deleterious galvanic corrosion (Figure C) . As an alternative strategy, highly electroactive Mg nano and microparticles have been embedded within PEI and epoxy/polyamide matrices, wherein they afford sacrificial cathodic protection. ,− …”

Reducing the wear and corrosion of the agricultural mower steel knives by electrodeposition nanocomposite coatings – Review

“…Hou in 2019 has been pinpointed that the cost of corrosion in the world is about 2.505 billion dollars and this represents 3.4 % of the gross national product (GNP) as shown in (Table1). In addition, the effective control of corrosion through modified coatings, new materials, and preventative maintenance is estimated to reduce this cost by 15-35% or as much as 875 billion dollars annually [11,12]. The cost of wear and friction in turkey is decreased by 337 million dollars due to improve the material used in the industry against corrosion and wear [13,14].…”