Rezumat
CZU 541.138.2
Corrosion was investigated on the samples of the electrodeposited copper (diameters of the electrode were 10, 25, 50, and 500 µm) obtained from a pyrophosphate electrolyte. Corrosion was studied in the same electrolyte (without the addition of a copper ion) by measuring pola-rization curves. It was demonstrated that for microelectrodes with the radius of 5 µm the corrosion rate increa-ses 8-fold compared to that of microelectrodes with the radius of 25 µm, while for microelectrodes with the radii in the range of 25–250 µm the measured corrosion rate did not change. It is illustrated that the investigated corrosion process is corrosion with oxygen depolarization (in the range of the radii of microelectrodes of 5–25 µm the reduction rate (dissolved oxygen) increases 8-fold). The results of measurements of the observed size effects are confirmed by calculations for the diffusion currents of microelectrodes, from which it follows that the size effect (an increasing density of the diffusion current with a decreasing size of the electrode surface) should be observed for surfaces with a radius of less than 20–30 µm.
Keywords: corrosion, pyrophosphate electrolyte, size effect, diffusion current, electrodeposition of copper.