The entire fleet of F-15s in the U.S. Air Force is getting primed for future flights, thanks to chrome-free inhibitor technology originally developed at the University of Missouri-Rolla.
Chrome-based coatings prevent corrosion of aircraft but also pose a health hazard to workers applying primer and paint. The first F-15 was treated with non-chrome primer earlier this year. The Air Force has now started a full production cycle involving the repainting of all F-15s in the fleet. The aircraft are repainted every six years or so.
“The chrome on your car bumper doesn’t present a health risk because the toxic form is the chromate,” says Dr. Thomas O’Keefe Sr., Curators’ Professor emeritus of metallurgical engineering. “But if you were to grind up that chrome and disturb materials and form the chromate, that would cause a potential health hazard. The risks are mainly associated with those involved in production.”
Applying chrome-based primer can cause severe respiratory problems, and in some cases may lead to lung cancer. The U.S. Occupational Safety and Health Administration (OSHA) plans to initiate new rules in 2006 to significantly reduce the amount of chrome exposure to U.S. workers.
While the Air Force is helping lead the way in reducing chrome-based risks to workers, primers with the non-chrome inhibitor may soon have a number of commercial applications too. Boeing Corp., along with the Air Force, has supported UMR’s research in this area since it began about 10 years ago.
The work at UMR attracted the attention of a company called Deft Industrial Finishes, which eventually licensed the chrome-free inhibitor technology from UMR and further developed it into paint formulations, including the primer used to coat the F-15s.
Though many researchers have played key roles in the process, UMR graduate Dr. Eric Morris, who is now employed by Deft, was a major contributor as a post-doctoral student. Morris says the research involved chemistry challenges and intellectual challenges.
“The materials you want to use as active corrosion inhibitors may not always be compatible with the paint,” Morris explains. “The problem with the materials that were compatible was they didn’t always perform well in providing the desired corrosion protection. We’re not the only ones who were trying to solve this problem.”
The answer, or at least part of the solution, occurred to Morris one day while bass fishing at a lake near Rolla. He won’t divulge secrets, but he says an idea came to him after observing how particular reactions occur slowly in nature. Back at UMR, with the help of faculty, he applied that observation to the team’s ongoing research.
“As long as you had an idea, faculty were always willing to support you,” Morris says.
With UMR’s permission and at Boeing’s invitation, Morris took new test panels coated with chrome-free primer to St. Louis, where he eventually met with Larry Triplett, who was leading Boeing’s Environmental Assurance Research and Development Group. Morris says he’ll never forget when Triplett turned to him and said, “You just might have something here.”
After earning his Ph.D. in chemistry at UMR in 2000, Morris continued his work by joining Deft, the company that licensed the chrome-free inhibitor technology from UMR.
UMR, Boeing and Deft have each played significant roles in the development of the chrome-free primers in production today, including those currently used by the Air Force.
“It’s a good example of how ideas move from academia to industry to implementation,” Morris says.
It takes approximately 10 gallons of the Deft primer to coat one F-15. The non-chrome primer, which can be sprayed through the same equipment used to apply the old chrome-based coating, is an aqua green color. The aircraft are later painted gray.
Dr. James Stoffer, Curators’ Professor emeritus of chemistry at UMR, was a principal investigator on the project, along with O’Keefe. Among the other researchers who have been involved are Dr. Paul Yu, a research assistant professor at UMR’s Materials Research Center, and Dr. Scott Hayes, who earned a Ph.D. in chemistry at UMR in 2005.