不同过电位下一维点蚀的近场动力学数值模拟

Numerical modeling of 1D corrosion pit propagation under different overpotentials using peridynamic method

利用近场动力学(Peridynamic,PD)模拟不同过电位下304不锈钢在1 mol/L NaCl溶液中一维(1D)点蚀的演化行为,并得到点蚀次表面层的材料损伤程度。利用法拉第二定律、Nernst-Planck质量守恒方程、阳极BulterVolmer电化学动力学方程与PD理论建立一维点蚀数学模型。通过物质点的相变来表征点蚀边界移动,当物质点的浓度小于电极边界处金属离子的饱和浓度时,则该物质点转化为液体物质点,点蚀边界向金属深处移动。模拟3种过电位下点蚀扩展,得到腐蚀引起的金属材料损伤层,并通过物质点的浓度来表征金属当前的损伤程度。将结果与其他文献结果相比较,验证PD点蚀模型的正确性。相对于其他的数值模拟方法,PD方法有其独特的优势,为模拟含不连续现场的物理场提供一种新方法。

The propagation of 1D pitting corrosion for different overpotentials was simulated by peridynamic（PD） method,as well as the damage of metal subsurface.The mathematic model of a dissolving body hosting a metal/solution interface which separated the solid metal electrode from the liquid electrode based on Nernst-Plank equation,Faraday＇s second law and Bulter-Volmer electrochemical kinetic law was derived.The moving interface was automatically evolved when a phase-change mechanism was accomplished.Results was validated by experiments on pit growth rate and polarization data for pitting corrosion.PD method had unique advantages to simulate discontinuous problem compared to the other numerical methods.