Copper microstructures (length 30 µm, diameter between 3 µm and 400 nm) are created by electrochemical deposition using etched ion track membranes as templates. The aim of this paper is to analyse the deposition process and to investigate the corrosion properties of the resulting structures. The pore filling has to be homogeneous in order to study the potentiostatic metal deposition systematically. Therefore, critical parameters are identified and optimised. As a next step, the effect of overvoltage on the prepared needles and the resulting current versus time curves is investigated. It is possible to establish a qualitative model for copper deposition within the pores of a template by analysing the recorded curves. For a given curve, up to six different time periods can be distinguished corresponding to the following processes: For very short times, the copper deposition is controlled by charge transfer. Then a transition region follows, where the overvoltage for charge transfer and diffusion are of comparable size. In the following three regions, the deposition process is controlled by diffusion. Initially the diffusion is linear inside the pores, because the thickness of the diffusion layer is smaller than the length of the remaining pore. Afterwards, the overall process is determined by radial diffusion of ions towards the pore openings. Finally, the copper deposition is characterised by a linear diffusion to the whole membrane surface. As soon as the pores are completely filled, caps start to overgrow the membrane surface. In addition, the corrosion properties of the prepared copper microstructures are studied and compared with those of macroscopic copper samples. For this, cyclic voltommagrams are recorded in 0.1 N sodium hydroxide solution and borate buffer. In sodium hydroxide, the occurring corrosion processes are very complex and hard to interpret due to high corrosion current densities and a large percentage of soluble corrosion products. Extensive systematic studies are performed in borate buffer, where the solubility of CuO and Cu(OH)2 is minimal and the observed corrosion current densities are much smaller. In conclusion, the investigations performed on microelectrode ensembles give no indication for specific corrosion properties of copper needles with dimensions in the micrometer range compared to macroscopic samples. | English |