DFT calculation of corrosion initiation of Fe-, Ni- and Al-base alloys and pure Cu caused by corrosive ions
Title: DFT calculation of corrosion initiation of Fe-, Ni- and Al-base alloys and pure Cu caused by corrosive ions
SNIC Project: SNIC 2021/5-223
Project Type: SNIC Medium Compute
Principal Investigator: Jinshan Pan <jinshanp@kth.se>
Affiliation: Kungliga Tekniska högskolan
Duration: 2021-05-01 – 2022-05-01
Classification: 10407 10402
Homepage: https://www.kth.se/profile/jinshanp/
Keywords:

Abstract

Corrosion of metal materials, either pure metals or alloys, causes degradation of the materials, which not only results in huge economic cost and environmental impact worldwide, but also may lead to catastrophes with loss of human lives. Corrosion initiates from metal surface due to chemical and electrochemical reactions with corrosive species in the service environment. The most harmful corrosive species are H, O, Cl, S atoms, molecules, and ions. Fast oxidation of metals by O2 and H2O leads to loss of the material. Cl ions can cause breakdown of protective passive film on the metal surface and initiation of dangerous localised corrosion. H atoms can easily enter into the the metal and cause degradation of the microstructure leading to hydrogen embrittlement. S can react with metal and form sulphides, enter into metals, and/or enhance the hydrogen ingress and corrosion cracking. Traditionally, corrosion studies are carried out by different experiments techniques to explore the kinetics and mechanism of the corrosion processes. The development of corrosion resistant metal materials for different applications, i.e., advanced high performance alloys, requires fundamental knowledge of the corrosion mechanism at molecule and atomic scale. Nowadays, state-of-the-art experimental techniques allow analysis of the surface and bulk microstructure of metal materials down to nano and atomic scale. Some of synchrotron and neutron techniques enable in-situ or operando analysis of the corrosion processes at atomic level. On the other hand, fast development of modelling tools enabled theoretical study of the corrosion processes at atomistic level, thus achieving fundamental understanding of the corrosion initiation and mechanisms. In recent years, in parallel to experimental measurements, we have employed DFT calculation to study the energetics of surface adsorption and dissociation of corrosive species, the work function and Volta potential of the metal surfaces, and insertion and transport of Cl, on simple systems. In this project, we aim to use DFT calculation to explore complex systems that are more relevant and comparable to experiments. The main objectives are to study the interplay between H, O, S and Cl in the surface reactions, the energetics of ingress and pathway of H, S and Cl in the surface oxides (passive film) and in the microstructure of pure metal (e.g., Cu) and alloy systems (Fe-, Ni- and Al-base alloys). Moreover, the strain within relevant oxides, either during oxide formation or oxide breakdown plays an important role in those atomistic behaviour, and H insertion in metal crystals can induce lattice dilation and strain in the microstructure. We will also perform DFT studies of these behaviour in parallel to our experimental studies of selected industrial alloys.