Phase-field model of pitting corrosion kinetics in metallic materials

Abstract

Pitting corrosion is one of the most destructive forms of corrosion that can lead to catastrophic failure of structures. This study presents a thermodynamically consistent phase field model for the quantitative prediction of the pitting corrosion kinetics in metallic materials. An order parameter is introduced to represent the local physical state of the metal within a metal-electrolyte system. The free energy of the system is described in terms of its metal ion concentration and the order parameter. Both the ion transport in the electrolyte and the electrochemical reactions at the electrolyte/metal interface are explicitly taken into consideration. The temporal evolution of ion concentration profile and the order parameter field is driven by the reduction in the total free energy of the system and is obtained by numerically solving the governing equations. A calibration study is performed to couple the kinetic interface parameter with the corrosion current density to obtain a direct relationship between overpotential and the kinetic interface parameter. The phase field model is validated against the experimental results, and several examples are presented for applications of the phase-field model to understand the corrosion behavior of closely located pits, stressed material, ceramic particles-reinforced steel, and their crystallographic orientation dependence. INTRODUCTIONCorrosion is the gradual destruction of materials (usually metallic materials) via chemical and/or electrochemical reaction with their environment. It costs about 3.1% of the gross domestic product (GDP) in the United States, which is much more than the cost of all natural disasters combined. Localized corrosion, such as pitting corrosion, is one of the most destructive forms of corrosion; it leads to the catastrophic failure of structures and raises both human safety and financial concerns. 1-3 Pitting corrosion of stainless steel usually occurs in two different stages: (1) pit initiation from passive film breakage 4-6 and (2) pit growth. 2,3,[7][8][9][10][11][12] In this study, we focused on the development of a phase-field modeling capability to study pit growth by considering both anodic and cathodic reactions.In the past few decades, great efforts have been made to develop numerical models for pitting corrosion. The moving interface and the electrical double layer at the metal/electrolyte interface are the two challenging problems faced by most of these numerical models. These numerical models can be divided according to the method in which a moving interface is incorporated in their models. Several steady state 9,10,13-18 and transient state 19-28 models have been developed over the years that did not allow for changes in the shape and dimensions of the pits/crevices as corrosion proceeds.Recent advances in numerical techniques, such as the finite element method, the finite volume method, the arbitrary Lagrangian-Eulerian method, the mesh-free method, and the level set method have encouraged researchers to model the evolving morphology...

Modeling the effect of insoluble corrosion products on pitting corrosion kinetics of metals

“…The major drawback of this model is its limitation to 1-D geometry problems, while PF models, in principle, should naturally extend to 2-and 3-D geometries without any changes in the formulation. Ansari et al 20 overcame this problem and proposed a PF model that showed good agreement with the experimental results in both 1-and 2-D cases. They also presented a set of examples to show the ability of their model to capture the effects of complex microstructures.…”

“…Readers are referred to our previous PF work where the effect of the variation of applied potential is studied in detail including a comparison with the experimental results. 20 In this work, we focus on the evolution of ICP and its role in corrosion kinetics. Now, the 1-D MPF model is used to simulate an ICP phase between the electrolyte and the metal.…”

“…The phase evolution of all three order parameters is governed by Eq. (20), where ψ a is a function of crystallographic orientation. Relative to the [111] plane, the corrosion potential is assumed to be 5% lower for [110] and 10% lower for [100].…”

“…Most of the numerical models ignore ICP formation completely or consider its effect implicitly. 11,13,16,20,24 Experimental findings indicate the importance of ICPs and their effect on corrosion rate and the morphology of the pits. 25 Some sharp-interface numerical models based on the ALE method have been presented, which do consider ICP formation.…”

Efeito da deformação plástica uniaxial na resistência à corrosão-fadiga do aço inoxidável ISO 5832-1

“…aço inoxidável pode apresentar zonas com tensões residuais, e, há indicações que a corrosão não seja uniforme nessas regiões, resultando em diferentes taxas de corrosão para diferentes direções. Segundo a literatura, zonas com tensão residual compressiva são menos facilmente corroídas do que zonas sem tensão residual, e estas, por sua vez, são menos suscetíveis à corrosão que zonas com tensão residual trativa(ANSARI et al, 2018).O efeito da tensão residual no comportamento de corrosão do aço inoxidável austenítico SUS 316L foi indicado na literatura (TAKAKUWA; SOYAMA, 2015). Corpos de prova foram tratados para se obter diversos acabamentos superficiais, de forma a excluir fatores além da tensão residual, tais como: textura, microdeformações e tamanho de grão, os relação ao meio com pH 7,2.…”