A local structure change of bulk Pd40Ni40P20 glass during full relaxation

The change in the amorphous structure of bulk Pd40Ni40P20 glass during structural relaxation was examined by an anomalous X-ray scattering (AXS) experiment with energies near the Ni K-absorption edge. It was confirmed by differential scanning calorimetry that the sample reached a meta-stable state (a fully relaxed state) with an equilibrium free volume concentration after annealing for about 1 × 104 s at 563 K and 4 × 104 s at 557 K just below the glass transition temperature Tg = 567 K. The structural changes on the progression toward a fully relaxed state were examined in samples annealed for 1 × 103 and 2 × 104 s at 563 K (glass A), and for 3.2 × 103, 1 × 104 and 7 × 104 s at 557 K (glass B). The structural analysis revealed that the coordination number of Ni–Ni like atom pairs increased with annealing time and that of Ni–Pd, unlike atom pairs, decreased. Meanwhile, the coordination number NPNi of P–Ni atom pairs and the nearest neighbor distance rPNi did not show a remarkable variation. However, prolonged annealing of 7 × 104 s at 557 K induced a remarkable change in NPNi and rPNi.