Researchers Work to Extend Ship Coating Life
WEDNESDAY, MAY 1, 2019
Researchers based out of the Corrosion and Coatings Engineering Branch at Naval Surface Warfare Center, Carderock Division (West Bethesda, Maryland), are testing and evaluating coatings that could help mitigate corrosion on Navy vessels.
In their work, engineer Charles White and chemist Kylee Fazende factor in different requirements in coating chemistry, including exposure to sunlight, temperature and biofouling. The team tests the survivability of coatings in different sea environments.
Vessel Coating Evaluation
Choices made must meet the requirements of Naval Sea Systems Command’s (NAVSEA) standard item numerical index, as well as meet approval of the corresponding technical warrant holders.
Researchers note that different areas of a ship require different coatings—each part of a hull is coated differently to account for environmental variables, and the coating used on a ship’s exterior, which will face warmer temperatures, will be different from what is used in the context of an air-conditioned interior.
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| Edvin Hernandez, U.S. Navy, public domain |
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In their work, engineer Charles White and chemist Kylee Fazende factor in different requirements in coating chemistry, including exposure to sunlight, temperature and biofouling. The team tests the survivability in different sea environments. |
“Anti-condensation coatings are used outside air-conditioned habitable spaces, but a lot of other parts of the ship do not have that commodity," said Fazende. "In those air-conditioned spaces, the surrounding bulkheads will start condensing water because of the difference in the temperature inside and outside."
“So you have to factor in that there’s going to be standing water on this wall permanently when selecting a proper coating.”
Fazende also noted that some coatings require specialized formulation to meet specific needs. A nonskid flight deck coating needs to be able to stand up to mechanical wear and a hot surface, for example. Color selection is also imperative.
“A black coating can work really well for some applications and deck camouflage until you start factoring how much sun it is going to absorb. You can get elevated deck temperatures very quickly,” said White.
Polysiloxane paint, a recent replacement for silicone alkyd, has exhibited better color retention, UV resistance and adhesion compared to earlier coatings.
White and Fazende use special chambers equipped to deliver an accelerated environment in testing coated panels. After the first wave of testing, both researchers go to one of Carderock's Florida detachments to carry out real-world testing.
“What we do here is shorter term, so it’s our way of being able to test the paints and be able to get an idea of how their performance is going to be. We have accelerated light exposure, salt spray and salt fog, which simulates what the ships would actually experience with humidity, water coming off of the waves and salt content in the air,” Fazende said.
White noted that both researchers do lab testing in West Bethesda, and then when the paint panels go to the South Florida Ocean Measurement Facility, the two do corrosion studies for the Marine Corps and for the Navy.
“Corrosion is one of those complicated multivariate processes that is difficult to control by addressing only one variable," White said.
"Many pathways for corrosion propagation and control exist, and the Corrosion and Coatings Engineering Branch is structured to address them as a team to make sure the Navy platforms and equipment stay in the best condition."
Tagged categories: Coating chemistry; Coating Materials; Coating Materials; Research and development; Ships and vessels; U.S. Navy
