Combinatorial Search for Pt-Free Amorphous Alloys as Glass Molding Die Materials(<Special Issue>M & P 2009 The 9th Materials and Processing Conference)

Abstract

This paper describes the search for novel Pt-free thin film amorphous alloys for use as optical glass lens molds. Two Ni-Nb-Zr thin film libraries were fabricated by a combinatorial arc plasma deposition. From the results of an X-ray diffractmetry and energy dispersive X-ray fluorescence spectrometry, the amorphous composition region was decided in the Ni-Nb-Zr system. Five Ni-Nb-Zr thin film amorphous samples that exhibited non-crystallization over 100h heating at 723K were re-fabricated using a carousel type sputtering system. The samples were evaluated in terms of various properties: mechanical properties, anti-sticking properties to molten glass, and machinability, in order to find the most suitable composition for the optical glass lens molding die. As a result, Ni_<35>Nb_<40>Zr_<25> was found to be a suitable composition for a glass lens molding die material. This sample exhibited fracture stress of 1.71GPa, excellent anti-sticking properties to molten glass, and good machinability, which was improved by modifying the fabrication method.