Measuring Aerosol Chlorides for Atmospheric Corrosion Studies in Cold Alaskan Climate

Abstract

Atmospheric corrosion is a complex process, which involves chemical, electrochemical, and physical changes to the metal exposed. Atmospheric corrosion occurs when a metal surface is under a thin layer of moisture, but not completely immersed, and the metal surface corrodes while exposed to environmental factors. Atmospheric corrosion of metal alloys in cold environments is assumed to be negligible and limited corrosion data are available in cold climates. However, studies in the Arctic and Antarctic regions have shown significant corrosion damages when exposed to cold conditions. The rate of atmospheric corrosion on various alloys is affected by environmental parameters that include temperature, rainfall, humidity, chloride-ion deposition rate, and time of wetness (TOW). Two important factors that affect atmospheric corrosion rates are aerosol chlorides and TOW. The main goal of this research is to monitor and measure the aerosols chlorides in the atmosphere, measure TOW and correlate the degradation of carbon steel alloys that are widely used in land, sea, and aerospace transportation, the oil and gas, fisheries, and mining applications. The main objectives achieved are design of Combined Chloride and Corrosion Portable Racks (C3PR) and deployment of C3PR racks in four different Alaskan environments. Chloride deposition rate measured using ASTM standards for three different exposure periods along with TOW, ambient temperature and RH data are correlated to the atmospheric corrosion rate of carbon steel to understand the underlying atmospheric corrosion mechanisms. The results from this research work will give a better understanding on the atmospheric corrosion studies in cold arctic/sub-arctic environment and lead to more externally funded projects.