Microporous morphology of cathodic electrolytic treated aluminum imaged by atomic force microscopy

We observed exceptionally large pores (1–2 μm diameter) on aluminum electrochemically treated at relatively low voltage bias (50 V) under cathodic polarization. The pore spacing and size did not correlate with the proportionality law of nanoporous aluminum oxide, and appeared at least one order of magnitude higher. We did no inquire the mechanism of pore formation, but verified its reproducibility and investigated the resulting morphology. The pores were more uniformly distributed than those resulting from chemical etching without electrical bias, and appeared almost twofold larger when cathodic treatment was potentiostatic (at 50 V) rather than galvanostatic (at 10 mA/cm2). The obtained surfaces appear promising for extended use as the substrate for living cell cultures, as scaffolds or permanent implant treatment.