Corrosion Inhibition of Sealants In An Aggressive Environment METSS 300 Westdale Avenue Westerville, OH 43082 Contact: Dr. Kenneth J. Heater Phone: (614) 797-2200 Fax: (614) 797-2201 Email: [email protected] Website: www.metss.com Contract Number: N68335-05-C-0181 PROBLEM STATEMENT Sealants applied between adjacent panels on aircraft are expected to last the life of the plane despite exposure to harsh environmental conditions, such as salt water and salt saturated air. The sealants are applied to protect the underlying substrate from corrosion caused by the environment. The primary problem is that the sealants themselves, primarily polysulfides, do not survive the harsh environmental conditions to which they are exposed, thus the underlying substrate is subject to attack. Due to increasingly stringent environmental regulations the use of hexavalent chromium is no longer a viable option for inhibiting corrosion. Consequently, new means of stabilizing the sealants and providing corrosion protection are required. TECHNOLOGY DESCRIPTION This program demonstrated that polysulfide sealants are degraded by oxidation, a process that reduced the sealants adhesive strength to an aluminum substrate and made the sealant material more porous, more brittle, and less durable. As a result of the oxidation process the aged sealants ability to protect the underlying METSS Page 1 of 2 Oxidative degradation of