In-situ investigations of the corrosion on metal surfaces

The oxidation behavior of pure metals and alloys has been a wide field of investigations during the last decades. While these previous studies mainly deal with multi-analytical ex-situ investigations of the corrosion products formed on a metal surface during degradation, the aim of this project is to elucidate the corrosion mechanism of pure metals and alloys in the early stages of corrosion in-situ by the aim of Tapping-Mode Atomic Force Microscopy (TM-AFM), InfraRed Reflection Absorption Spectroscopy (IRRAS) and Quartz Crystal Microbalance (QCM) as well as by additional ex-situ Secondary Ion Mass Spectrometry (SIMS) measurements. The main focus of this project is directed to the atmospheric corrosion behavior of pure silver and its alloys because of the vital role of these materials in modern semiconductor devices due to the lowest electrical resistivity in metals. Already a thin tarnish film on silver can influence the operational readiness negatively particularly with regard to the nowadays occurring miniaturization of such units. Therefore the knowledge of the exact reaction mechanism of the weathering process is necessary to develop strategies and methods to prevent these reactions. Furthermore the application of silver nano-particles as integral part for the microbial inhibition of synthetic potable water containers requires investigations of the corrosion mechanism. Even though there were diversified ex-situ investigations of the tarnishing process of pure silver there is still a lack of the detailed knowledge of the reaction mechanism taking place during weathering with or without acidifying gases such as SO2, OCS or NOx. As could be shown in previous studies on copper and its alloys there is a discrepancy of the results obtained by in-situ methods to those used for the identification of the corrosion products ex-situ. The project aim is to clarify the exact mechanism of the silver oxidation and sulfidation by atmospheric pollutants such as SO2, NO2, and H2S in dependence of the humidity content of the surrounding atmosphere as well as the influence of alloy constituents such as gold. The influence of other oxidation parameters such as UV-light shall also be clarified within this project.

The oxidation behavior of pure metals and alloys has been a wide field of investigations during the last decades. While these previous studies mainly deal with multi-analytical ex-situ investigations of the corrosion products formed on a metal surface during degradation, the aim of this project is to elucidate the corrosion mechanism of pure metals and alloys in the early stages of corrosion in-situ by the aim of Tapping-Mode Atomic Force Microscopy (TM-AFM), InfraRed Reflection Absorption Spectroscopy (IRRAS) and Quartz Crystal Microbalance (QCM) as well as by additional ex-situ Secondary Ion Mass Spectrometry (SIMS) measurements. The main focus of this project is directed to the atmospheric corrosion behavior of pure silver and its alloys because of the vital role of these materials in modern semiconductor devices due to the lowest electrical resistivity in metals. Already a thin tarnish film on silver can influence the operational readiness negatively particularly with regard to the nowadays occurring miniaturization of such units. Therefore the knowledge of the exact reaction mechanism of the weathering process is necessary to develop strategies and methods to prevent these reactions. Furthermore the application of silver nano-particles as integral part for the microbial inhibition of synthetic potable water containers requires investigations of the corrosion mechanism. Even though there were diversified ex-situ investigations of the tarnishing process of pure silver there is still a lack of the detailed knowledge of the reaction mechanism taking place during weathering with or without acidifying gases such as SO2, OCS or NOx. As could be shown in previous studies on copper and its alloys there is a discrepancy of the results obtained by in-situ methods to those used for the identification of the corrosion products ex-situ. The project aim is to clarify the exact mechanism of the silver oxidation and sulfidation by atmospheric pollutants such as SO2, NO2, and H2S in dependence of the humidity content of the surrounding atmosphere as well as the influence of alloy constituents such as gold. The influence of other oxidation parameters such as UV-light shall also be clarified within this project.