Effect of Sputtering Method on Characteristics of Amorphous Ni—Nb—Zr Alloys for Glass Lenses Molding Die Materials

Abstract

We investigated the characteristics of amorphous Ni—Nb—Zr alloys for fabricating dies for molding high-precision optical glass lenses. Two amorphous Ni—Nb—Zr samples with similar compositions were prepared using carousel-type and parallel plate sputtering systems; we refer to these samples as the synthesized sample and the target sample, respectively. These two samples were evaluated and compared the desired characteristics for molding dies for optical glass lenses, namely a high mechanical strength, a high hardness, a thermally stability of amorphous state, a high oxidation resistance, a similar linear expansion coefficients to that of glass, and a high machinability. The thermal stability of amorphous state, oxidation resistance, and linear expansion coefficient did not depend on the fabrication method, whereas the mechanical properties, hardness, and machinability did. In particular, the target sample exhibited excellent mechanical strength and machinability. Finally, we fabricated a molding die made from amorphous Ni₃₅Nb₄₀Zr₂₅ alloy for optical glass lenses using diffraction gratings.