Atmospheric corrosion of zinc coatings - a time and laterally resolved study

摘要

One of the main issues nowadays concerning atmospheric corrosion studies is the reproduction of field conditions in the laboratory. Spectroscopic methods have established themselves as sensitive and solid measurement methods for corrosion studies. Especially via Raman spectroscopy valuable in situ information can be generated. Within the scope of this work various zinc coatings were investigated in a field exposure. The samples were studied ex situ by IRRAS/Raman/GDOES and SEM to provide a comprehensive picture of the corrosion products formed on the coatings. Complementary to field exposure, laboratory studies of these samples were conducted with spectroscopic methods including a weathering cell to create a corrosive atmosphere and to simulate field conditions. The influences of various pollutants such as road salts or corrosive gases were investigated. Systematically complex corrosion processes and interactions could be studied. The aim of the study was to identify the role of different pollutants concerning the atmospheric corrosion of zinc coatings and to create artificial lab conditions which may yield the same resuks as field exposure in a shorter period of time. In contrast to many other corrosion studies of zinc, the experiments were both time and laterally resolved and additionally gave new insights in local corrosion phenomena, which is of great interest for processes like Cl~- induced corrosion.