Author(s)

A. S. TOLOEI, V. STOILOV & D. O. NORTHWOOD

Abstract

The effect of unidirectional surface roughness on the corrosion behaviour of nickel in 0.5 M H2SO4 solution was investigated using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The surfaces, both before and after corrosion, were characterized by scanning electron microscopy, profilometry for roughness and energy dispersive spectroscopy for oxygen content. The results were compared with those for patterned samples consisting of an array of holes. For the unidirectional surface roughness samples, an increase in roughness gave rise to an increase in corrosion rate, reflecting the decreased ability to form a stable passive film. The patterned samples showed a higher corrosion resistance, which is attributed to a different corrosion protection mechanism, namely heterogeneous wetting.

Keywords

Corrosion, nickel, passive layer, patterned surface, unidirectional roughness