Computational design and optimization of multilayered and functionally graded corrosion coatings

TitleComputational design and optimization of multilayered and functionally graded corrosion coatings
Publication TypeJournal Article
Year of Publication2013
AuthorsCross, SR, Woollam, R, Shademan, S, Schuh, CA
JournalCorrosion Science
Volume77
Pagination297 - 307
Date Published2013/12//
Abstract

This paper describes a computational approach to analysis and optimization of compositionally graded coatings for cathodic protection. Time-dependent galvanic corrosion is simulated by coupling a finite element electrochemical model with calculated rates of metal dissolution. A simulated annealing optimization algorithm is applied to the time-dependent corrosion model to determine coating structures that maximize desired protective qualities. This computational approach to coating design is applied to a hypothetical graded zinc-alloy coating with a circular defect on an iron substrate, in an aerated NaCl electrolyte. A linear compositional gradient increases the predicted duration of cathodic protection by 84% over an equivalent monolithic coating, while the optimized coating structure further improves protection time to a total increase of 112%. The optimized coating structure consists of a thin barrier layer adjacent to the substrate, with a thicker sacrificial layer on the exterior and a short region of graded composition in between. The overall approach to optimization of coating structure is shown to be robust, efficient, and produce non-obvious designs with significant improvement in coating performance, and thus has potential to be of significant utility in practical corrosion coating design. (C) 2013 Elsevier Ltd. All rights reserved.