Fabrication and corrosion behavior of Ti-based bulk metallic glass composites containing carbon nanotubes

This study explored the feasibility of preparing Ti50Cu28Ni15Sn7 bulk metallic glass composite with powder metallurgy. With high energy ball milling of a pure Ti, Cu, Ni, Sn and carbon nanotube (CNT) powder mixture, the CNT/Ti50Cu28Ni15Sn7 metallic glass composite powders can be formed with mechanical alloying ( MA) after 8 h milling. The bulk metallic glass composite was successfully prepared by vacuum hot pressing the as-milled CNT/Ti50Cu28Ni15Sn7 metallic glass composite powders. The corrosion behavior of the Ti50Cu28Ni15Sn7 bulk metallic glass as well as composites modified by the addition of CNT was investigated by electrochemical measurements. Electrochemical characterization was performed in Hanks' solution at 37 degrees C with physiologically relevant dissolved oxygen content. The results of potentio-dynamic polarization measurements revealed that the Ti-based bulk metallic glass composites examined showed spontaneous passivity by anodic polarization with a passive current density of about 10(-5) A/cm(2). The higher corrosion resistance of the Ti-based bulk metallic glass composites was attributed to stable and protective passive films enriched with titanium containing certain amounts of additional elements. (C) 2010 Elsevier B.V. All rights reserved.