Corrosion and oxidation properties of the refractory (Ni8Nb 5)99.8Sb0.2 bulk metallic glass

Abstract

Bulk metallic glass (BMG) with high corrosion resistance and high oxidation resistance was synthesized in the Ni-Nb-Sb system with the diameter of 3mm. The glass transition temperature (Tg), the reduced glass transition temperature (Trg=Tg/Tl) and supercooled liquid span (ΔTx) are 873K, 0.59 and 54K, respectively. These thermal data indicate that this kind of Ni-based glass can maintain its stable amorphous state and resist crystallization in a rather wide temperature region. Electrochemical measurements indicate that it shows high corrosion resistance in aggressive hydrochloric acid solution with 1N and 6N concentration, respectively, at room temperature. Surface forms stable passive film and presents low current density. The oxidation kinetics follows a parabolic rate law at 853K. The x-ray diffraction pattern showed that the oxide layer is composed of Nb2O5, Ni3Nb and metallic Ni. The oxide surface morphologies showed that a layer of compact oxide film formed, which shows no obvious grain boundary. © 2009 IOP Publishing Ltd.