Dr. Luz M. Calle, the technical lead for Kennedy Space Center’s Corrosion Technology Laboratory, checks out sample tiles at the Beachside Corrosion Test Facility. (NASA.gov image)
BREVARD COUNTY • KENNEDY SPACE CENTER, FLORIDA – Corrosion is a real concern at NASA’s Kennedy Space Center in Florida. Exposure to humidity, salt, ultraviolet light and exhaust from rocket launches can start the condition in facilities and metal structures.
Of special concern are the launch pad and ground support equipment currently being prepared for the agency’s Space Launch System and Orion spacecraft.
Scientists at Kennedy, including Luz M. Calle, Ph.D., technical lead for the center’s Corrosion Technology Laboratory in the Research and Technology Programs Directorate, have developed an environmentally friendly smart coating that could be used in the future to detect and stop corrosion in metal.
This innovative technology, called “Smart Coating for Corrosion Detection and Protection,” was recognized by NASA Tech Briefs magazine’s “Create the Future Design” contest with the top award in the automotive and transportation category.
Calle accepted the award on behalf of the team during a ceremony Nov. 6 in New York City.
Dr. Luz M Calle
“We are known for launching rockets, but we are not thought of as a place where interesting technologies like smart coatings are being developed,” Calle said.
“It’s good to be recognized by people outside of Kennedy Space Center in a worldwide contest. Corrosion of metals is a very serious and costly problem worldwide,” said Calle.
“But, here at Kennedy Space Center, we have one of the most corrosive environments in the world, certainly the most corrosive in North America.
“The natural environment at Kennedy is extremely corrosive due to the combination of ocean salt spray, heat, humidity and sunlight. With the introduction of the space shuttle in 1981, the already highly corrosive conditions at the launch pads became even more severe with the acidic exhaust from the shuttle’s solid rocket boosters.”
Calle explained that one way to protect metals from corrosion is by applying a coating to them. This creates a barrier between the metal and the environment. But when the coating is damaged, its ability to protect against corrosion stops.
Another way to prevent corrosion is to add corrosion inhibitors to the coating. But, Calle said, there are several problems with current inhibitors. Though very effective, many of them are harmful to humans and the environment. Top on that list is hexavalent chromium, widely used in the aerospace industry for protection of aluminum.
Calle said finding environmentally friendly corrosion inhibitors that don’t interact with the coating is challenging. The coating doesn’t adhere as well or destroys the inhibitor, and sometimes problems can arise if a lot of inhibitor has been added to the coating.
Calle said the idea for smart coating technology was born in 2004 and work to develop it has continued throughout the years. Corrosion inhibitors can be packaged inside tiny micro capsules or micro containers, developed in the Corrosion Technology Laboratory at the Operations and Checkout Building. The containers are porous and less than one-tenth the size of the diameter of a human hair.
Sponsors of the NASA Tech Briefs magazine’s “Create the Future Design” contest are with Dr. Luz M. Calle, top winner in the automotive and transportation category for the innovative technology “Smart Coating for Corrosion Detection and Protection.” From left, are Sumit Awasthi, Global E-Commerce Channel manager; Calle; Dr. H.C. Svante Littmarck, COMSOL Group chief executive officer; and Marilyn Cooper, Mouser Electronics corporate supplier manager. (NASA.gov image)
The micro capsules are added to the coating, and they remain dormant until corrosion begins underneath the coating. That’s where the “smart” portion of the technology kicks in. The shell of the micro capsules are designed to break open and deploy the corrosion inhibitor.
“We call them feedback active micro containers, because they respond to what is happening around them,” Calle said. “They’re not passive. They just know what to do. Basically, the shells break down and deliver the corrosion inhibitor, and then they disintegrate.”
Another type of delivery system being developed is a micro container that is porous. The corrosion inhibitor is trapped in the pores, similar to water being trapped in a sponge. When the corrosion starts, the inhibitor is released to do its work.
An issue at launch pad sites has been the problem of corrosion to large bolts. On the surface they look good, but the corrosion is taking place inside the bolt. Calle’s team is working on encapsulating color-changing corrosion indicators in coatings.
“If we have a coating with micro capsules that contain a corrosion indicator that changes color when corrosion is present on the inside, then it will be evident from the outside that there is a problem,” Calle said.
Smart coating samples are being tested at the Beachside Corrosion Test Facility, which is located near the launch pads.
“We are working with several industry partners in the coatings and automotive industries because we are interested in transferring this technology so it can be available to everyone,” Calle said.
The “Create the Future” design contest was launched in 2002 by the publishers of NASA Tech Briefs magazine to help stimulate and reward engineering innovation. The annual event has attracted more than 10,000 product design ideas from engineers, entrepreneurs and students worldwide.
This year’s competition attracted 1,150 entries in seven different categories from more than 60 countries.
