Adhesion of Low Emissive coatins on PMMA Substrates.

摘要

Aircraft canopies are exposed to erosion during flight. It is difficult to combined the desired optical and mechanical properties of canopy coatings. It is favorable to have a low emissive coating on the canopy in order to reduce the emitted infrared radiation from the cockpit as well as reduces the emittance from the canopy caused by aerodynamic heating. The final multilayer structure includes a layer of Teflon for protection, but this report is focused on the adhesion between the substrate and the metal film. Visually transparent layers of titanium nitride, gold, silver, and aluminum were deposited by sputtering onto PMMA substrates. Prior to the deposition, the substrates were cleaned in a glow discharge process in the load lock chamber. The surface modification of the cleaning process aimed at improving the adhesion of the thin metallic layer. However, the Scotch 3M tape test indicates that the adhesion was not improved by the pretreatment of the substrate surface. A water jet test, to study the rain erosion resistance, showed that the extra layer of metal did not effect the abrasive properties of the surface. From literature, it is known that a surface treatment of glow discharge improves the adhesion of metal layers on plastic surfaces. Therefore, additional work on the treatment prior to sputter deposition needs to be done.