Aufklärung der elektrochemischen Mechanismen bei der Anodisierung in hochviskosen Elektrolytlösungen

A novel pressure-sensitive adhesive tape was used for anodization of aluminum. The main difference between this anodization tape and conventional bath anodization is the viscosity of the electrolyte. While the viscosity of bath anodization is in the same range of water, the viscosity of the adhesive matrix is higher by seven orders of magnitude. The impact of the high viscous electrolyte on the anodization process and the morphology of the anodic oxide layers was investigated. The limitation of mass transport in the high viscous electrolyte slows down oxide formation and dissolution during anodic oxide growth. With in-situ electrochemical impedance spectroscopy a reduction of the effective area during tape anodization could be determined. Step-like voltage changes during the anodization process lead to the formation of different sublayers in the porous oxide layer, which allow the calculation of oxide formation and oxide dissolution rates for both anodization types.