PROJECT: Development of Test Sites and Atmospheric Corrosion Studies of Metal Alloys and Coatings Exposed to Cold Arctic/Sub-Arctic Climate
Science PI: Raghu Srinivasan, Assistant Professor, UAA
Co PI: Lei Zhang, Associate Professor, UAF
It is commonly assumed that there is very little to no corrosion in cold environments. However, previous studies in the Antarctic and Arctic regions have shown significant corrosion damage when exposed to cold conditions. Moreover, very little corrosion data are available for metal alloys exposed to cold arctic and sub-arctic conditions. 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. Three important factors that affect atmospheric corrosion rates are aerosol chlorides, SO2 and time of wetness (TOW) along with other climatic parameters such as rainfall, temperature, humidity, and solar radiation. Aerosol chlorides can be carried to the metal surface both by natural means (wave/surf action or salt-laden snow from the marine environment) and by man-made pollutants (deicing salts on roads). Similarly, SO2 can also be deposited via natural means (volcanic) and man-made pollutants (combustion of fossil fuels). With the recent climate change in the arctic and sub-arctic region, there is a renewed interest to study the atmospheric corrosion mechanisms. The combination of urbanization and proximity to marine/volcanic environments make arctic and sub-arctic regions in North America, particularly Alaska, an important natural laboratory to study atmospheric corrosion in cold regions.
Goal and Objectives: The main goal of this proposal is to understand the underlying atmospheric corrosion mechanisms of metal alloys and coatings exposed to cold arctic climate. The main objectives of this proposed research are:
- To establish atmospheric corrosion test sites across the state of Alaska equipped with weather stations.
- To study the effect of sample orientation and snow/ice retention on the corrosion rates and study the ingress of air-borne chlorides and oxygen transportation through varying thickness of snow/ice.
- To evaluate the performance of an already developed anti-corrosion polymer nanocomposite coatings (PNCCs) in natural environments for aerospace applications.
Alignment with NASA: Corrosion continues to be a major problem of NASA since its inception in 1962 and it is included in NASA’s Space Technology Roadmap to reduce the cost and improve the sustainability and efficiency of its ground operations in support of future launch activities. According to the NASA Space Technology Roadmap, corrosion prevention, detection and mitigation fall under TA 13 Ground and Launch Systems (TA 13.2.1). One of the grand challenges is to predict the corrosion life of materials systems in actual service conditions. Testing in actual atmospheric condition will also help in devising modified accelerated corrosion testing for better correlation. It is of great importance to study the limits of chemical and electrochemical stability of metal alloys and coatings under extreme conditions, which includes cold artic climate. The proposed project monitors the degradation of metal alloys that are widely used in land, sea and aerospace transportation and the data obtained will enhance the understanding of atmospheric corrosion mechanisms in cold arctic climate.
NASA Mission Directorate Collaboration: This project directly aligns with NASA Kennedy Space Center’s Mechanical and Environmental Test Laboratory and complements their facility in Florida. Collaborations with the NASA lab (Dr. Eliza Montgomery) will allow specific corrosion problems to be identified and tested in cold arctic climate conditions. Metal samples will be to deployed at the Beachside Atmospheric test site at KSC to get reference data for the metals exposed to hot tropical marine environment.
Area of Expertise: The proposed research requires expertise in the field of corrosion and coatings. Science PI Dr. Raghu Srinivasan has extensive experience investigating corrosion rates and mechanisms associated with atmospheric corrosion.