Bulk Glassy Pd-Cu-Ni-Cr-P Alloys Containing Dispersed Nanoparticles Prepared by Copper-Mold Casting

Abstract

This paper presents a finding of producing nanoparticle dispersed bulk glassy alloys in a Cr-modified Pd–Cu–Ni–P (PCNP) system by using a copper-mold casting technique. The PCNP alloys with the compositions near Pd₄₀Cu₃₀Ni₁₀P₂₀ possess high glass-forming ability (GFA) resulting from their exceptionally small nucleation rate. Cr additions in Pd₄₀Cu_30−xNi₁₀P₂₀Cr_x (x=1–5 at%) alloys result in homogenous nucleation of Ni₃₃Cr₃₃P₃₄ when these alloys are solidified from liquid state. The composition of the remaining liquid changed to that near Pd₄₀Cu₃₀Ni₁₀P₂₀ by the precipitation of Ni₃Cr₃₃P₃₄ and the matrix can be easily solidified to a glassy phase, leading to the formation of a mixed structure consisting of nanoscale Ni₃₃Cr₃₃P₃₄ particles embedded in a glassy phase. The particle size is significantly affected by alloy composition and cooling rate.