A Novel method for the Large-Scale Production of Calcium Lanthanum Sulphide (CLS) Nanopowders for Optical Ceramic Applications

Military LWIR sensor windows and domes have been traditionally plagued by high maintenance and replacement costs due to soft, erosion prone ZnS and ZnSe materials. The high replacement cost of 100 units per year at $50,000 plus/unit for the Forward Looking Infrared (ATFLIR) ZnS window assembly on F-18s is a prime example.  Transparent Ca2La2S4(CLS) with a broad 2–16 micron transmission window, higher hardness and potential strength more than twice that of ZnS has long been a highly desirable replacement. Until this Phase 1, despite numerous research and development projects, no CLS powder processing effort produced cost effective, high purity CLS nanopowders capable of consolidated optical ceramics with 60% transmission from 6-16 microns and strengths twice that of previous CLS materials. The Phase-II proposal details systematic steps for optimizing the attractive Phase 1 synthesis process, scaling up to multi-kilogram quantities, and demonstrating consolidation methods capable of achieving 60% or greater transmission, superior strength and rain erosion resistance in scaling to realistic size samples. With follow on Phase 3 and/or Manufacturing Technology program funding, a sound commercialization strategy with a high probability of success is outlined.