Alaska Space Grant awarded to engineering alumnus to study Arctic corrosion

As winter approaches, many are once again scrambling to prepare their belongings to withstand the cold — from coats, hats and gloves to ski gear and snowmachines. Others think about the effects of the cold on pipes and engines. Such anticipation is something mechanical engineering alumnus Tyler Cushman is working on but on a much larger scale.

In June 2021, Cushman was awarded funding from the Alaska Space Grant Program, established under a grant from NASA's National Space Grant College and Fellowship Program. The award will fund his graduate fellowship to work on Measuring Aerosol Chlorides for Atmospheric Corrosion Studies in Cold Arctic Climate, one of seven projects awarded the ConocoPhillips Arctic Science and Engineering Endowment Award in 2020. If the title is any indication, the research itself is similarly complex.

“I personally didn't ever think I would have any sort of association with NASA,” said Cushman. “I'm just some kid from Alaska, but it felt great to be recognized on a project that is important.”

Metals inevitably corrode and return to their natural oxide state when an electrolyte solution is present on their surface. Corrosion is accelerated when two metals with different reduction potentials (tendency to acquire electrons) are touching and have an electrolyte pathway via solution between them. This creates a galvanic cell in a process called galvanic corrosion. This process can also occur in a single metal with regions of different reduction potentials, creating what are called anodic and cathodic sites. Even with a very small amount of moisture such as that present in the atmosphere, atmospheric corrosion occurs. 

In Alaska, accounting for atmospheric corrosion is of particular interest to some of the state’s largest industries and the structures they maintain, such as the pipelines that snake through the freezing tundras and the docks that withstand the crashing ocean waves.

“Mainly this is going to give people an idea of what to expect for a corrosion rate in certain metals within Arctic climates,” said Cushman. “If you're trying to build some big carbon steel structure in Fairbanks, you might say, ‘Well in Tyler's test it only corroded at this rate and this is what we're expecting, so we can build it with this material because we know it's going to last this long.’ Or when building in Kodiak where it's more severe one might say, ‘Maybe we want to get an alloy that's more corrosion resistant so it might last longer in a relatively aggressive environment.’” 

Working under the project principal investigator and UAA mechanical engineering Assistant Professor Raghu Srinivasan, Ph.D., Cushman has designed and fabricated four test racks — tripods that hold different metal samples at zero-, 30- and 45-degree angles to control how fast water and snow run off of the metals. Over a period of eight months, these test racks will study how the differing propagation of moisture on the samples affects corrosion rates. 

Additionally, the test racks contain what Cushman refers to as a chloride candle — essentially moisturized gauze wrapped around a test tube that will collect aerosol chlorides in the water and snow built up on the metal samples. This attachment will allow Cushman to study the specific effect that aerosol chloride has on corrosion rates.

Two of the four test racks will remain here in Anchorage — one will be placed on top of the parking garage next to UAA’s Engineering and Computation Building, and the other at the Port of Anchorage. A third test rack will be placed near the Fairbanks International Airport to observe Arctic corrosion away from the ocean.

Lastly, the final test rack will be placed near the Pacific Spaceport Complex in Kodiak. Through the Alaska Space Grant Program funding, findings at this location will help expand NASA’s understanding of how corrosion specifically impacts launch sites in colder weather climates, as opposed to the warm, sunny, humid locations home to all of NASA’s own sites.

“We have a general idea of atmospheric corrosion rates in the Arctic, but there just hasn't been much testing done,” said Cushman. “I think that’s why NASA and other big entities are showing interest, because they see the utility of Alaska.”

Beyond Alaska and NASA, Cushman speculates that his research can lead to wider corrosion mitigation efforts that can lift a substantial financial burden from the United States, recalling that around 3.5% of global gross domestic product is spent directly on corrosion annually, with an additional 6% spent indirectly.

Funnily enough, Cushman’s involvement in a project with the potential to be so impactful nearly didn’t happen. The first time he applied for Alaska Space Grant Program funding was rejected. However, thanks to the encouragement of Srinivasan, he threw his hat into the ring a second time.

“As a mentor and graduate advisor, I am really happy that Tyler got this fellowship through ASGP,” said Srinivasan. “This introduces a graduate to higher studies in the STEM area and most importantly it has relevance to NASA and a chance to work closely with top NASA corrosion scientists. He thoroughly deserves this ASGP graduate fellowship award.”

Cushman hopes to one day return the favor to his university and his community — any broader benefits are an added bonus.

“My goal is to stay in Alaska and have a fruitful career here,” said Cushman. “I'm really thankful for UAA. They’ve given me great opportunities and I've worked with some really bright people. I don't know if there's a way that I could give back, but hopefully this research brings some light and funding from these big entities like NASA, because we have some great professors in the engineering field here at UAA.”

 

This material is based in part upon work supported by NASA through the Alaska Space Grant Program (80NSSC20M0070).