Atmospheric corrosion is a process that is heavily dependent on weather parameters. Heavy snowfall and dramatic freeze-thaw cycles observed in Arctic conditions further complicate the atmospheric corrosion mechanisms. The main purpose of this paper is to monitor and measure weather parameters, aerosol chlorides, and sulfates in the atmosphere and correlate it to the degradation of carbon steel alloys widely used in land, sea, aerospace transportation, oil and gas, fisheries, and mining applications. Carbon steel alloys (UNS G10060) were exposed to four atmospheric test sites in Alaska, representing distinct environments. Multi-angle test racks were designed, equipped with chloride candles and weather stations, and deployed to each site. The parameters recorded were Time of Wetness (TOW), relative humidity (RH), temperature, and aerosol chloride and sulfate deposition rates. The corrosion rate of carbon steel was calculated from the mass loss data. Accelerated laboratory tests were conducted in cyclic corrosion test chambers (CCTC) following the modified GM9540P standard for correlation studies.
Atmospheric corrosion of metal alloys in cold environments is assumed to be negligible1. However, studies in the Arctic and Antarctic regions have shown significant corrosion damage when exposed to cold conditions2. While thermodynamically this is correct, other factors in such environments can be responsible for driving corrosion. Studies in regions of Canada, Norway, and Russia show that not only are corrosion rates in the low-temperature areas substantial, but when compared to less developed frigid regions (Antarctic), the corrosion rates are substantially higher2. This indicates that the pollutants of urbanization in such regions also accelerate corrosion. Alaska's harsh arctic meteorological factors, along with both natural and manmade aerosols, influence atmospheric corrosion3. These predominant aerosols mainly consist of sea salt and de-icing salt. These salts are hygroscopic in environments of critical relative humidity and increase the Time of Wetness (TOW). TOW is defined by the ISO 9223:1992(E) as follows: "The period during which a metallic surface is covered by adsorptive and/or liquid films of electrolyte that are capable of causing atmospheric corrosion 4". The freezing point for deicing salts can also be lowered to -50°C, melting the layer of ice and snow present on the sample's surface, increasing the wetness and driving corrosion5. The combination of urbanization and proximity to marine environments make North America's Arctic and sub-Arctic regions, particularly Alaska, a strategic location for commerce, military defense, and space exploration.
