The effect of ionic peneration on semiconducting behaviour of temporarily protective oil coating on the surface of AISI 304 stainless steel

✍ Scribed by Q. Zhong; M. Rohwerder; L. Shi

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: German
• Weight: 526 KB
• Volume: 56
• Category: Article
• ISSN: 0947-5117
• DOI: 10.1002/maco.200503868

✦ Synopsis

Abstract

In this paper, the semiconducting behaviour of temporarily protective oil coatings on the surface of naked and prepassivated AISI 304 stainless steel immersed in 3% aqueous NaCl solution was studied by utilizing potential‐capacitance methode, Mott‐Schottky analysis and impedance analysis. It was pointed out that the temporarily protective oil coating behaves as a semiconductor during its degradation. The ionic penetration and the substrate greatly affect the conduction behaviour of the oil coating. On the surface of naked AISI 304 stainless steel, the oil coating behaves as a n‐type semiconductor. With increasing immersion time, the donor density of the space charge layer in the temporarily protective oil coating increases from 10^19^ to 10^25^ m^−3^. However, on the surface of the prepassivated substrate the space charge layer in the oil coating is significantly affected by the oxide on the steel electrode. In this case immersion time does not influence the density of charge carriers in the oil coating (10^21^ m^−3^). Impedance analysis also verify above results.