Protective coatings for chalcogenide glass molding

Driven by high-priced technical devices such as thermal imaging cameras, molding of infrared glass is recently a rapidly growing market. To ensure an efficient infrared glass molding process, protective coatings are required to prevent the degradation of the molding tools. For this reason, this work investigates the operational capability of protective coatings for chalcogenide glass molding. Two nitride-based coatings and a precious metal coating were tested. Heating tests as well as molding tests were carried out on industrial glass molding machines. Analyzing subsequent degradation mechanisms, light microscopy, white light interferometry, scanning electron microscopy and transmission electron microscopy were performed. In conclusion, a CrAlN coating could be identified that can withstand thermochemical and thermomechanical loads in precision molding of chalcogenide glass.