Novel Erosion Resistant Coatings for Zinc Sulfide(1001-471)

In airborne optical systems where multispectral zinc sulfide windows are employed there is a need to improve the environmental durability of the windows. The most common solution employed for the purpose of improving the rain and sand erosion resistance of a multispectral ZnS window is to coat the window with a harder material. Alumina and diamond like films are popular examples. The problem with the “hardcoat” solution is that where as the materials themselves are resistant to erosion, the very same material properties that result in “hardness” are ideal for the propagation of impact vibrations to the coating/substrate interface. This impact vibration propagation results in continued damage to the zinc sulfide and that rapid deterioration of the window’s optical performance. Triton Systems, Inc. proposes to develop a novel coating with enhanced erosion protection capability to circumvent some of the issues with the current coatings. The coating will be highly transparent in the visible and MWIR spectral regions. BENEFIT: The demonstration of a rain and sand erosion resistant coating for multispectral zinc sulfide with high transmission in the MWIR and visible spectral regions that can be practically applied to a variety of substrates geometries and sizes will be significant for the future development of coatings tailored towards several applications of interest to both the military and commercial markets, specifically, the optics, electronic display, building, automobile, and aircraft industries. We expect the developed coatings to significantly improve ZnS window erosion resistance and at least double window service lifetime. The coating process that will be used in this program can be tailored to meet the specific requirements of a broad range of substrate geometries requiring high performance erosion resistant films. Further, the coating process will be rugged and relatively inexpensive. The resulting erosion resistant coating technology should have numerous applications in additional military and commercial equipment and products where ZnS windows are employed