Fe_(3)O_(4)膜层海洋腐蚀行为及机理的ReaxFF-MD研究  

nvestigation on the Marine Corrosion Behavior and Mechanism of Fe_(3)O_(4)Film Using ReaxFF-MD

作　　者：陈祥锐 陈杨[1] 王冰[1] 古斌 CHEN Xiangrui;CHEN Yang;WANG Bing;GU Bin(School of Manufacturing Science and Engineering,Southwest University of Science and Technology,Mianyang 621000,China)

机构地区：[1]西南科技大学制造科学与工程学院,四川绵阳621000

出　　处：《材料保护》2024年第11期18-27,共10页Materials Protection

基　　金：国家自然科学基金(12102372)。

摘　　要：为了更深入和全面地探究钢材在海洋环境中发生腐蚀行为的内在机制,采用反应力场分子动力学(ReaxFF-MD)方法研究了钢钝化膜成分Fe_(3)O_(4)在不同NaCl含量、温度和应变条件下的海洋腐蚀行为,通过表征表面腐蚀形貌、测试质量损失曲线、数密度曲线、径向分布函数(RDF)曲线、模拟反应界面处的原子结构演化,分析了不同条件下Fe_(3)O_(4)海洋腐蚀行为的过程和差异,从原子尺度揭示了Fe_(3)O_(4)海洋腐蚀和不同因素影响的机理。结果表明:Fe_(3)O_(4)的海洋腐蚀经历3个阶段:海洋环境中水分子在Fe_(3)O_(4)基体表面的吸附阶段、基体快速腐蚀阶段和腐蚀饱和阶段。在腐蚀过程中,海洋环境中NaCl含量的升高会促进水分子在基体表面的吸附,增强基体原子与水分子间的相互作用;温度的升高会引起膨胀变形和分子运动的增强,降低基体原子发生断键行为的难度;外加应变则导致Fe_(3)O_(4)基体内部的原子键键长增加和原子配位数减少,从而加剧腐蚀进程。此外,当外加载荷作用时,基体中的应变随着腐蚀的进展而增大,并在高应变加载情况下产生缺陷集中区域。In order to explore more deeply and comprehensively the intrinsic mechanisms of corrosion behavior of steel in the marine environment,the ReaxFF molecular dynamics(ReaxFF-MD)method was employed to study the marine corrosion behavior of Fe_(3)O_(4)in steel passivation film under different NaCl contents,temperatures and strain conditions.By characterizing the surface corrosion morphology,testing the quality loss curve,number density curve,radial distribution function(RDF)curve and simulating the atomic structure evolution at the reaction interface,the process and differences of Fe_(3)O_(4)marine corrosion behavior under different conditions were analyzed,and the mechanisms of Fe_(3)O_(4)marine corrosion and the influence of different factors were revealed at the atomic scale.Results showed that the marine corrosion of Fe_(3)O_(4)went through three stages:the adsorption stage of water molecules on the surface of Fe_(3)O_(4)substrate in marine environment,the rapid corrosion stage of substrate and the corrosion saturation stage.During the corrosion process,the increase in NaCl content in the marine environment promoted the adsorption of water molecules on the substrate surface,enhancing the interaction between substrate atoms and water molecules.Moreover,the increase in temperature would cause expansion deformation and enhance molecular motion,reducing the difficulty of bond breaking behavior of matrix atoms.External strain led to an increase in atomic bond lengths and a decrease in atomic coordination numbers within the Fe_(3)O_(4)matrix,thereby exacerbating the corrosion process.Besides,when the external load was applied,the strain in the substrate increased with the progression of corrosion,and the defect concentration area was generated under high strain loading.

关 键 词：钢钝化膜 Fe_(3)O_(4) 海洋腐蚀 ReaxFF-MD模拟 海洋应力腐蚀 

分 类 号：TG172[金属学及工艺—金属表面处理]