CERAMIC FASTENERS FOR AIRCRAFT JOINING APPLICATIONS

The proposed Phase I program addresses key challenges to the development of ceramic-based mechanical fasteners for Naval aircraft applications. Specific applications of interest for the ceramic fasteners include high temperature joining regions of aircraft such as in the vicinity of engine exhaust, and also for use in the joining of aluminum airframe components to the galvanically dissimilar graphite fiber reinforced epoxy matrix composite panels. Existing titanium fasteners begin to lose stiffness and strength properties at temperatures as low as 2000F. Couples set up by the transmission of galvanic current from graphite/epoxy composites to metal components lead to degradation of the composites and corrosion of the metals. The use of coatings on the composite and sealants applied to the outside and mating surfaces of the metallic components has been demonstrated to be effective in reducing the galvanic action of the couples. This practice works successfully until a joint is reached, where a galvanic conduction path from the edge of the aluminum component to the edge of the composite is provided by the metal fasteners. Ceramic fasteners will be investigated as a potential solution to both of the technical problems posed by the use of the metal fasteners. This project will be performed with the engineering and technical assistance of Bell Helicopter and DuPont Lanxide, which will act as subcontractors to MSNW.