Bulk formation of a metallic glass: Pd40Ni40P20

Abstract

Molten spheroids of Pd₄₀ Ni₄₀ P₂₀, of up to 0.53‐cm minor diameter, were slowly cooled (1.4 K/s) on a fused silica surface under 10⁻⁶ Torr vacuum to a form which was entirely glassy except for some superficial crystallinity comprising less than 0.5% of the volume. The occurrence of crystallization was eliminated by subjecting the specimens to surface etching followed by a succession of heating and cooling cycles. The absence of crystallization in the bulk was confirmed by x‐ray diffraction, transmission electron microscopy, and calorimetry. Using the last technique, the heat of crystallization of the glass was measured to be 5.3±0.3 kJ/g atom.