Air oxidation of a Zr55Cu30AL10Ni5 bulk metallic glass at its super cooled liquid state

Air oxidation behavior of a Zr(55)Cu(30)AL(10)Ni(5) bulk metallic glass was investigated in its super cooled liquid region. The oxidation kinetics follows a single-stage parabolic rate law at low temperatures and changes into a two-stage parabolic rate law with temperature increasing. The kinetics transition is proved to be caused by crystallization. Parabolic rate constants of both stages increase with temperature, while the corresponding transition time decreases. Surface segregation phenomena were observed on oxidized samples. The segregated particles become larger and denser with the increase of heating temperatures and heating durations, and their compositions are verified to be Cu and O. (C) 2014 Elsevier Ltd. All rights reserved.