Anti-sticking Re-Ir coating for glass molding process

• Re and Ir monolayers, and Re/Ir multilayer coatings for molding glass were evaluated.
• Multilayer films exhibited better anti-sticking ability than monolayer coatings.
• Anti-sticking improvement of the multilayers was due to the addition of interfaces.

The sticking of glass to the dies is a critical problem in glass molding process which limits the quality of products and lifespan of mold. Three kinds of protective coatings, including monolayer Re, Ir and Re/Ir multilayer were designed to mitigate the sticking and to improve the lifespan of mold. The interaction between barium crown optical glass and WC/Co mold materials (Co-10 at. %) with these three protective coatings was investigated. The results demonstrated that anti-sticking performance of multilayer coating is better than that of monolayer Re, Ir coating. The addition of interfaces resistance in multilayer is the main reason for improvement of anti-sticking ability of multilayer Re/Ir film. It was also verified that the Re/Ir multilayer coating possesses the highest nanohardness (24.5 GPa), as well as the largest wetting angle (168.1 °).