A research team, coordinated by the Oklahoma Aerospace and Defense Innovation Institute at the University of Oklahoma, is working with members of the 76th Maintenance Wing at the Oklahoma City Air Logistics Complex to develop a novel chromium-free organic primer for aerospace applications.

John Klier, Ph.D., dean of Gallogly College of Engineering and co-principal investigator for the research project, is leading the project alongside Brian Grady, Ph.D., a professor in the School of Chemical, Biological and Materials Engineering, in partnership with the Oklahoma City Air Logistics Complex. OC-ALC technical leads are Blake Yort and Ross Moseley.

Currently, chromium compounds are added to paints and primers to provide protection against corrosion and create certain colors. Hexavalent chromium is a toxic form of chromium with can cause severe health effects to those exposed, according to the Occupational Safety and Health Administration.

“Hexavalent chromium is the benchmark in corrosion protection but is also a known carcinogen and environmental hazard. Removing chromium from the primer will eliminate worker exposure during depot and field maintenance. The Air Force spends billions of dollars per year on corrosion maintenance, so it is critical that any new primers provide equivalent corrosion protection,” said Evan Mertes, with the 76th Maintenance Wing.

Klier says they are working to evaluate and identify epoxy-based primer compositions that help the U.S. Air Force eliminate the use of hexavalent chromium and reduce environmental impact and the associated costs with its use and disposal.

“These primers will provide excellent corrosion protection and adhesion to pretreated aluminum alloys while offering exceptional fluid resistance and outstanding flexibility,” he said.

Klier said the research team has developed several chrome-free prototype additive systems, and that spray and testing infrastructure are in place. Application and evaluation of the formulation are underway. The two-year project is expected to be completed in 2023.