Copper Dissolution Rate as a Function of the Corroding-Surface Tilt

Measurements of the copper corrosion rate in 0.5 M H2SO4 as a function of the tilt angle of the corroding electrode surface in the gravitational field show that the downward flux of natural convection (NC), which arises during corrosion, effects the process similarly to NC that arises when electrochemical reactions proceed in a diffusion kinetics mode. The corrosion rate of a horizontal face-down electrode is 2.3 times that when facing up. Without NC, when a horizontal face-up copper electrode is in a recess, its corrosion rate is defined by the oxygen diffusion current and is 12–28 times as small as that with NC next to its surface.