Open-Loop Electric Potential Microscopy （OL-EPM） is the evaluation method that enables measurement of potential distribution on the metal surface in liquid, but the relationship between the surface potentials in liquid and atmosphere is not clear. Therefore, we attempted to compare the potential distribution in atmosphere using Kelvin probe Force Microscopy （KFM） to the potential in liquid using OL-EPM at the same position on the aluminum alloy. As a result of the observation, the potential distribution obtained with OL-EPM in deionized water showed similar results to KFM. On the other hand, in corrosive environments the potential distribution showed local corrosion cell, which revealed that the potential distribution obtained with OL-EPM is different from that with KFM.

The effect of snow cover depth on the corrosion behavior of steels in a snowy environment was evaluated. Differences in snow-melting conditions, which due to heat derived from the height from the ground （floor of building roof）, affected the formation of water film and rust on the surface of the steel. The amount of corrosion for 100 mm was larger than that for 800 mm due to the formation of rust and the dissolution of Fe^2＋ ions caused by the maintenance of the water film. The orientation of the test surface also affected the maintenance of the water film. When the test surface was facing upward, the water film spread over the entire surface and rust occurred, while when the test surface was facing downward, rust occurred only in the area in contact with snow and the amount of corrosion was reduced.