MSU Technologies

Treatment Process for Reduced Corrosion in CFRP/Metal Hybrids

Executive Summary

Carbon fiber reinforced polymer composites (CFRPs) are often mechanically fastened to metals such as aluminum alloys in lightweight aircraft applications. Since both materials are electrically conductive, galvanic corrosion of the less noble metal can occur, leading to degradation over time. MSU researchers have developed a new technology for treating the exposed carbon fibers in the CFRP parts that significant inhibits corrosion. Salt spray test results for mechanically fastened treated CFRP to aluminum over 14 days show a 2/3 reduction in weight loss and ¼ of the surface roughness of the aluminum compared to untreated systems. The treatment also significantly reduces carbon fiber degradation and corrosion.

Description of the Technology

This invention involves treating the exposed edges of the CFRP with substituted aryl diazonium salts to form an organic adlayer covalently bonded the carbon fiber surfaces. The organic adlayer inhibits the rate of electrochemical reactions occurring at the carbon fiber-solution interface, thus inhibiting galvanic corrosion and carbon corrosion. The process can be accomplished spontaneously by immersing the exposed CFRP edges to a solution of the aryl diazonium salt over a period of time or by an electrochemically-assisted process. A range of aryl diazonium molecules can be used with excellent performance.

Benefits