Combined Thermally and Electrically Conductive Adhesives

"Following successful initial testing during Phase I, we are proposing continuing the development of both paste and film adhesive candidates during the first half of the Phase II program, then qualifying one of the adhesives for the F-22 radar sub-arrayproduction program. The prototype paste adhesive has already exceeded F-22 bonded joint thermal and electrical conductivity requirements with a metallic filler that will preclude galvanic corrosion of the aluminum substrate. The key Phase II challengewill be developing this paste to meet the unique F-22 assembly requirements necessary for maximizing production labor and cycle time savings. Significant improvements in current needle dispensed paste processing will be essential in making this adhesive aviable candidate: rapid large area dispense coverage (up to 1 square foot in a few minutes); maintaining tight tolerance component location and moderate adhesive strength of large bond areas during a fast pre-cure stage; and maintaining an easy reworkcapability ( 10 cm2 bond area). Using metallic coated fibers oriented in the z-axis, the prototype film adhesive came close to meeting the bonded joint conductivity requirements. Phase II development will use a heaviermetallic coating to ensure sufficient conductivity margin. The key Phase II challenge will be to modify the polymeric adhesive formulation so that a low pressure (<15 psi) applied during componen