Water adsorption behavior on metal surfaces and its influence on surface potential studied by in situ SPM

• Published in: Applied surface science Vol. 258; no. 22; pp. 9087 - 9091
• Main Authors: Guo, L.Q., Zhao, X.M., Bai, Y., Qiao, L.J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2012; Elsevier
• Subjects: Adsorption; Calibration; Chromium; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Force–distance curve; Humid air; Humidity; Metal coatings; Metal surfaces; Microscopy; Physics; SKPFM; Surface chemistry; Surface properties; Water film; Metal coatings; Water film; Force–distance curve; SKPFM; Humid air; Water; Metal coating; In situ; Force-distance curve; Surface potential
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2012.06.003

► Force–distance curves were established to characterize the thickness of water layer. ► The thickness of water layer on metal surfaces increased with the rise of humidity. ► The thickness of water layer and its variation are different for different metal. ► The corrosion potential decreases with the water adsorption on the metal surfaces. ► The corrosion potential of gold is the highest and that of chromium is the lowest. The water adsorption behavior on the surfaces of chromium, copper and gold and its effect on the surface potential at various relative humidity were studied by in situ scanning Kelvin probe force microscopy (SKPFM) combined with force calibration. The thickness of water layer on different surfaces was obtained from the force–distance curve. It increases with the rise of humidity. The Volta potential map was measured using SKPFM within a wide humidity range of 20–100% as a function of the thickness of water layers. The surface potential decreases with the increasing thickness of water layers on the metal surfaces. The difference in the water adsorption behavior and its effect on surface potential originates from the different surface properties of three metals, such as the roughness and contact angle.