For decades, the Department of Defense (DoD) has used coating systems that contain hexavalent chromium (Cr(VI)) in the form of chromates to prevent corrosion on military weapons systems, particularly aircraft. Because chemical compounds containing Cr(VI) are toxic and carcinogenic, in 2009 DoD initiated a policy to eliminate where possible their use as long as there was no loss in performance. In recent years, rare-earth compounds have shown promise as environmentally benign corrosion inhibitors in conversion coatings and primers. Still, the exact mechanisms by which these alternatives work remained unknown, limiting their usefulness.
Dr. Bill Fahrenholtz and his team from the Missouri University of Science and Technology and Deft, Inc. have made fundamental discoveries in understanding how rare-earth compounds containing cerium or praseodymium inhibit corrosion. Their research determined that the appropriate phase of a rare-earth compound has to be incorporated into the proper type of coating to provide corrosion protection in specific environments.
Through their efforts, Dr. Fahrenholtz and his team have dramatically advanced DoD’s understanding of these compounds and how they inhibit corrosion. Not only does the research of Dr. Fahrenholtz and his team represent a significant scientific achievement, it also exemplifies a highly successful collaborative effort between a university and private industry. The results of this project will provide direction for further development of rare-earth compounds as surface treatments and coatings for the military that will reduce the use of toxic Cr(VI) compounds while providing corrosion protection.
For this groundbreaking work, Dr. Fahrenholtz and his team received a 2012 SERDP Project of the Year Award. Project Overview
Missouri University of Science and Technology