Thermal roughening transition of a dissolved nickel surface

A thermal roughening transition in a polycrystalline nickel surface dissolved anodically by a rectangular pulse current is found. The drastic change in normalized dissolution mass at the transition temperature is shown to be consistent with that in surface roughness such as a smooth or rough surface. The normalized dissolution mass below the transition temperature exponentially decreases with the frequency of the rectangular pulse current and asymptotically approaches a fixed value much less than 1.0. The normalized dissolution mass above the transition temperature is almost equal to 1.0 irrespective of the frequency. The frequency dependence of the normalized dissolution mass is described by an electric circuit model equivalent to an electric double layer.