Joining Carbon Composite Fins to Titanium Heat Pipes

Everybody knows that composites have high strength, low density, and great thermal properties. They would be great for a number of applications such as fins for spacecraft radiators. So why aren't they used more on spacecraft thermal systems? One reason is joining technology. Although many methods such as brazing and adhesives have been developed for joining composites to metals, these methods are generally inadequate for high temperature operation, surviving launch vibration and thermal cycling and all the other "gotta-haves" required by spacecraft designers. Space Exploration Associates, teamed with BeamAlloy Corp., propose a radical new method for joining dissimilar materials. The idea is to bombard composite surfaces with metal ions, forming a super-adherent metal layer, which is bonded at the atomic level. Then the metals can be joined by application of pressure and temperature to make a nice, neat, nearly indestructible bond. The key is the use of special 500,000 volt accelerates to inject atoms directly into the atomic lattice of the host material. Preliminary experiments have resulted in bonds for nickel to carbon carbon, gold to molybdenum and even a combination of gold to rubber. Try that with a conventional brazing method. Applications range include radiator fins, turbine blades and even golf clubs.