Xiao Penghao, Orme Christine A, Qiu S Roger, Pham Tuan Anh, Cho Seongkoo, Bagge-Hansen Michael, Wood Brandon C
Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada.
Materials Science Division, Lawrence Livermore National Laboratory, Livermore, CA, USA.
Nat Commun. 2025 Jan 2;16(1):341. doi: 10.1038/s41467-024-54627-x.
Aqueous corrosion of metals is governed by formation and dissolution of a passivating, multi-component surface oxide. Unfortunately, a detailed atomistic description is challenging due to the compositional complexity and the need to consider multiple kinetic factors simultaneously. To this end, we combine experiments with a first-principles-derived, multiscale computational framework that transcends thermodynamic descriptions to explicitly simulate the kinetic evolution of surface oxides of Ni-Cr alloys as a function of composition, temperature, pH, and applied voltage. In the absence of pitting, we identify three distinct voltage regimes, which are kinetically dominated by oxide growth, dissolution, and competitive dissolution and reprecipitation. Evolving compositional gradients and oxide thickness are revealed, including a transition between a metastable Ni-Cr mixed oxide and a thick, porous Ni-dominated oxide. Beyond elucidating the underlying physics, we highlight the need for competing kinetics in models to properly predict the transition from passivation to corrosion. Our results provide a key step towards co-design of alloy composition alongside environmental conditions for sustainable use across a variety of critical energy and infrastructure applications.
金属的水腐蚀受钝化多组分表面氧化物的形成和溶解控制。不幸的是，由于成分复杂性以及需要同时考虑多种动力学因素，详细的原子描述具有挑战性。为此，我们将实验与基于第一性原理的多尺度计算框架相结合，该框架超越了热力学描述，以明确模拟Ni-Cr合金表面氧化物随成分、温度、pH值和外加电压的动力学演化。在没有点蚀的情况下，我们确定了三种不同的电压状态，它们在动力学上分别由氧化物生长、溶解以及竞争性溶解和再沉淀主导。揭示了不断演变的成分梯度和氧化物厚度，包括亚稳态Ni-Cr混合氧化物与厚的、多孔的Ni主导氧化物之间的转变。除了阐明潜在的物理原理外，我们还强调了模型中竞争动力学对于正确预测从钝化到腐蚀转变的必要性。我们的结果为合金成分与环境条件的协同设计迈出了关键一步，以实现跨各种关键能源和基础设施应用的可持续使用。
