Joining of UHTC to a Substrate for ultra-high temperature performance

As Hypersonic weapons enter the arsenal of the US Army, it will be essential that the outer surfaces of these weapons be of a heat resistant layer. Since these weapons will be flown within the atmosphere; oxidation, corrosion, high temperature and environmental protection will all be essential for the aero structures surface. Temperatures on nose tips and leading edges could reach high temperatures in an oxidizing environment. This makes most materials, if not all, except for UHTCs unable to survive under these very high temperatures. It is essential to have a layer of UHTC present on top of the underlying substrate at these very high temperature areas on Hypersonic aero structures. Most missions for Hypersonic systems are a few minutes in length, and therefore a layer of a UHTC is all that is necessary.Ā Surviving these mission environments for short windows of operation by joining UHTC to a substrate is the challenge. As always, in joining dissimilar materials, the coefficient of thermal expansion mismatch resulting in applied thermal mechanical loads in the key issue especially when thermal loads are close to a shock application.Ā The interface between a protective coating and a substrate with their different CTEÆs end up placing the thermal mechanical stresses exactly on that interface between the two materials. Typically, these interfaces are brittle or have clearly defined planes that exist between the two materials and therefore establish a cleavage plane.Ā Peregrine proposes a unique method of surface preparation on a substrate that allows it to receive infused high temperature particles of ceramics.Ā This approach will join UHTC to the substrate and provide a robust and durable coating to prevent recession during flight.