Transparent Oxynitride Coatings for High Speed Missiles Application

The oxynitride group of coatings, based on ternary phase diagram of silicon, carbon and nitrogen with the addition of oxygen, also known as SiCON, has potential for use as hard and durable coatings for high speed missile windows and domes. During the Phase I effort, Surmet successfully demonstrated the feasibility of depositing durable coatings of Si, SiN, SiC and SiCON using its innovative plasma-enhanced chemical vapor deposition (PE-CVD) technique. Surmet proposes a two phase program for the Phase II effort. In the basic award phase Surmet proposes application of SiCON coatings to full scale prototype windows/domes for two applications: THAAD and Common Missile. We propose to make a THAAD window out of ZnS (for extended mid-wavelength infra red (MWIR) performance), and to use the SiCON coating as a means of increasing its' durability. We also propose to produce an ALON Common Missile dome, with transparent conductive coating (TRANSCONTM coating) on its interior surface. In this case, the SiCON coating will be used to protect the TRANSCON coating from environmental degradation. In the proposed option phase, Motheyes and/or sub-wavelength structures (SWS) will be etched into the surface of the relatively high index SiCON coatings to provide anti-reflection function while preserving the durability of the SiCON coating.