Evaluation of multi-layered graphene nano-platelet composite coatings for corrosion control part II – Cathodic delamination kinetics

Abstract

Graphene nano-platelets (GNP) reduce corrosion-driven cathodic delamination rates.  GNP act principally to slow through-coating oxygen diffusion when coated on iron.  When the GNP are coated on zinc, a galvanic couple is formed.  The galvanic coupling of the GNP and zinc may displace cathodic oxygen reduction.

Cathodic delamination kinetics of thin polystyrene model coatings bound to zinc via organosilanes

“…In addtion, results of a control experiment with spin coated PVB are also shown. The curves show the typical shape and progression through the experiments . Initially, the potential of the intact polymer/metal interface, ≈0.0–0.2 V, is obtained.…”

“…Especially ion mobility can also be assessed at insulator surfaces, permitting separation of different reactions . More recently, self‐healing coatings were realized with α →0 after certain times, due to a slow‐down in cathodic delamination rate . In addition, cross over between different exponents has been observed .…”

General vapour-phase galvanizing and duplex coatings

“…This kind of coating, referred to as galvanized (GI) coating, cannot guarantee long-term protection against corrosion [6]. So, GI sheets are usually finished by an organic paint layer [8,9]. The skin pass prints a small depth and small pitch roughness that blurs the appearance of zinc grains, makes the surface look dull, and improves the adhesion of the organic layer.…”

Praseodymium-decorated graphene oxide as a corrosion inhibitor in acidic media for the magnesium AZ31 alloy

“…[36][37][38][39][40][41][42][43][44][45][46][47] In recent years, functionalized graphene oxide materials have been reported, such as poly(urea-formaldehyde), tin oxide, plasma based, and epoxy + graphene composite coatings, graphene ink, covalently functionalized N-graphene oxide, and ionic liquids, which are excellent corrosion barrier layers on alloy surfaces because they are impermeable to electrolytes and gas molecues. [48][49][50][51][52][53][54][55][56][57][58] Furthermore, GO functional groups can also enhance electron donation and accepting from the alloy surface. 59,60 The predominant properties of functional graphene oxide materials have a signicant impact on overcoming corrosion failure.…”