磁致涡流效应对阳极铝箔形貌及比电容的影响

针对盐酸-硫酸体系,通过耦合外加磁场对铝箔进行直流电化学腐蚀,系统研究磁致涡流效应(MagnetoHydrodynamics,MHD效应)对铝箔电化学行为、界面行为以及质量传递的影响。采用X射线衍射(XRD)、低温氮气吸附、扫描电镜(SEM)等手段对腐蚀箔样品进行表征。同时,通过计时电位法、极化曲线、循环伏安法、电化学阻抗法研究MHD效应对铝箔电化学性能的影响。结果表明,MHD效应能够抑制氧化膜的生长,增加铝箔表面Cl-的吸附量,减小扩散层厚度,强化Cl-/Al3+向孔内/孔外的传质,减小电解液中离子传递阻力。通过引入磁场,明显提高了腐蚀箔的蚀孔密度、平均孔径以及平均蚀孔深度的均一性,继而增大了阳极电子铝箔的比电容。

Effects of Magnetohydrodynamics on Morphology and Specific Capacitance of Anode Aluminum Foil

The magnetic field was introduced into the direct current electrochemical corrosion of aluminum foil based on HCl-H₂SO₄ system. The effect of magnetohydrodynamics (MHD) on the electrochemical behavior, interface behavior and mass transfer of aluminum foil were studied. The etched foil samples were characterized by XRD, N₂ adsorption and SEM. Meanwhile, the MHD effect on the electrochemical properties of aluminum foil was studied by means of chronopotentiometry, polarization curve, cyclic voltammetry and electrochemical impedance spectra. The result show that the MHD effect can inhibit the growth of aluminum oxide film, and strengthen the inward/outward migration of Cl^- and Al³⁺ within tunnels by thinning the thickness of the diffusion layer and decreasing the mass transfer resistance of ions in electrolyte. Moreover, with the help of magnetic field, the uniformity of etching hole density, average pore diameter and average hole depth are obviously improved, further improving of the specific capacitance of anodic aluminum foil.