Production of Ni-Pd-Si and Ni-Pd-P amorphous wires and their mechanical and corrosion properties

Abstract

Wire-shaped nickel-based amorphous alloys exhibiting high strength and good ductility combined with a high corrosion resistance were produced for Ni-Pd-Si and Ni-Pd-P alloys by melt spinning in rotating water. The amorphous wires were formed over a relatively wide range from 29 to 82 at % palladium for (Ni-Pd)₈₂Si₁₈ alloys and from 12 to 52 at % palladium for (Ni-Pd)₈₀P₂₀ alloys. The Ni-Pd-Metalloid amorphous wires had a circular cross-section and smooth surface, and their diameters were 80 to 150μm. With increasing nickel content, their tensile strength, σ_f, increased from 1340 to 1710 MPa and the elongation to fracture, ε_f, decreased slightly from 2.2% to 1.9%. Cold-drawing the wires was an easy technique to reduce their diameter and to increase σ_f and ε_f up to an appropriate value of reduction in diameter. In addition, it is also effective in smoothing the wire surface. Their corrosion resistance was assumed to be sufficiently high since their polarization behaviour in 1 N H₂SO₄ solution was similar to palladium metal. Cold-drawing did not enhance corrosion and rather decreased apparently the active dissolution current density of some alloys owing to smoothing of the surface.