OS5(1)-4(OS05W0022) Wetting Behavior of Micro-Water on Pure Chromium

概要

論文の詳細を見る
Recent researches on atmospheric corrosion of steels have been aimed at increasing their useful life. Corrosion occurs on metal surfaces when they are wetted by rain, moisture or dew because corrosive O_2,So_x, NO_2 or Cl-can easily be absorbed on these surfaces. Particularly, and the integrity or reliability of electronic information systems might be damaged even if slight corrosion occurred. Accordingly, it is necessary to investigate the characters of the condensed water on metal surfaces before giving a solution for the corrosion problem. Although the instabilities might be produced when using the non-contact mode of atomic force microscope (AFM) to image the micro-water, the authors have succeeded in observing them and evaluating their micro-wettabilities on several materials by means of the ac non-contact mode of AFM with decreasing the scanning speed and the tapping load. The obtained results show that the nano-size (micro-) water droplets are very stable in ambient air and more wettable than milli-size (macro) water droplets. However, the reason for the lower contact angles by micro-droplets than that by micro- ones had not been clear. In this work, the surface compositions of wet polished and air oxidized pure chromium, and the micro-wetting behavior of distilled water on these surfaces, were investigated with X-ray photoelectron spectroscopy (XPS) and the AC non-contact mode of AFM. Both an organic contaminant/water layer and a chromium oxide/hydroxide layer, where the oxide/hydroxide layer was beneath the contaminant/water layer, were detected by XPS analysis on each surface. The oxide/hydroxide layer became thicker, and the ratio of oxide to hydroxide became larger, after air oxidation. In ambient air, the AFM showed a thin liquid layer on each surface, easily moved by the cantilever of the AFM, and which could be condensed or evaporated. The inner part of the liquid might be adsorbed water, and the outer part of it was thought to be organic contaminant since the liquid would not combine with distilled water applied by post-wetting. Micro water droplets deposited by post-wetting always occupied positions with little or none of this liquid, which might explain the observed higher micro- than macro-wettability.
一般社団法人日本機械学会の論文
2003-09-09

OS5(1)-4(OS05W0022) Wetting Behavior of Micro-Water on Pure Chromium

スポンサーリンク

概要

著者

関連論文

スポンサーリンク