1998 Volume 47 Issue 6 Pages 384-390
We have measured the Kelvin potential, Vkp, of a low-alloy steel covered with adsorption water and a thin solution layer using the Kelvin probe apparatus. It was found that the Kelvin probe can detect the water adsorption both on the surface and in the surface oxide layer. Under a thin solution layer, corrosion potential, Ecorr, is dependent upon the thickness of the solution layer due to change in oxygen reduction rate and in surface characteristics. Long-time Ecorr measurement shows that Ecorr increases with time as a result of rust-layer formation on the steel surface; magnitude of which depends on characteristics of the rust-layer. The scanning Kelvin probe reveals the Vkp distribution for the steel surface with depositions of solution droplet and iron oxide.