In Situ Mass Spectrometric Reaction Monitoring of Atmospheric Corrosion Processes

A set‐up for in situ mass spectrometric reaction monitoring of gas phase mediated reactions is presented. Important constructive parameters for a reaction chamber for the investigation of atmospheric corrosion processes is discussed. The presented cell is especially well suited for atmospheric corrosion studies but it can easily be modified to be applicable in other fields of research as well. The atmospheric corrosion of electrolytically deposited zinc surfaces on steel during wet‐ and dry‐cycles is investigated as a model reaction. Corrosion rates as well as current densities during the first wet‐ and dry cycle are calculated and discussed. Complementary scanning Kelvin probe (SKP) measurements are performed to show the electrochemical changes occurring at the metal/air‐interface throughout the corrosion process. Contact potential difference versus distance measurements performed in advance to determine the maximum measurement distance, which allows investigating rough salt loaded sample surfaces via SKP surface scans. The anodic metal oxidation and the cathodic oxygen reduction are frequently the basis of atmospheric corrosion processes. With the oxygen reduction being the predominant cathodic reaction one can use oxygen consumption rates to determine the corrosion rate of a metal. In this work mass spectrometry is used to in situ measure oxygen consumption rates.