SUS 304ステンレス鋼の原子スケール平坦化

抄録

An atomically flat surface is very difficult to make on a less novel bulk material, for the surface of the material is ordinarily covered with rough oxide film in air.
In the preparation of a test specimen we deposited 304 stainless steel on the (111) surface of silicon substrate by ion-assisted sputtering. Oxide film, which was formed on the deposited 304 SS after sputtering process were removed in a 0.1 M sulfuric acid solution by cathode reduction method, and then the surface potential was quickly shifted to passive state and was held on at the state for 15 minutes in the solution. After picked up from the solution and dried up, the treated surface of the specimen placed in air was observed with scanning tunneling microscope.
The dimension of particle-like structure increased from 30 nm to 130 nm in diameter in several hours. The atoms on the structure were arranged at the steps of which step-terrace structure was constructed in the duration. The observed atoms were determined as oxygen according to an angle-resolved X-ray photoelectron spectrometry (XPS) analysis. The atomically flat surface of the step-terrace structure lasted for about 100 hours in air. Such a flat surface is expected to be of practical use for the suppression of corrosion occurrence.