Searching for Pt–Zr–Ni thin film amorphous alloys for optical glass lenses molding materials

This paper describes the search for Pt–Zr–Ni thin film amorphous alloys for use as optical glass lens molds. Six Pt–Zr–Ni thin film amorphous samples were fabricated by means of a carousel-type sputtering system. The samples were evaluated in terms of various properties: crystallization temperature (Tx), hardness, coefficient of linear expansion, anti-sticking properties to molten glass, and machinability, in order to find the most suitable composition for the optical glass lens mold. As a result, Pt50Zr36Ni14 was found to be a suitable composition for a new molding material. This sample exhibited a Tx of 985 K, a hardness of 8.2 GPa, a similar the coefficient of linear expansion of glass material, excellent anti-sticking properties to molten glass, and good machinability, which was improved by modifying the fabrication method. Finally, we fabricated a glass lens mold with diffraction gratings from Pt50Zr36Ni14 amorphous alloy.