Effect of Heat Exposure on Grain Growth and Oxidation Behavior of Cobalt Based Composite Powders by Facile Suspension Synthesis

Abstract

In this study the intermetallic-matrix composite powders CoNiCrAlY-2wt. %Al2O3 were characterized in order to investigate the effect of heat exposure time on morphologies, grain growth and phases formed by facile suspension route synthesis. The as-synthesized powders were examined by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) and X-ray diffraction (XRD). The formation of NiAl phase was noticed after 1 hour of heat treatment. The average particle size of intermetallic-matrix composite powders CoNiCrAlY-2wt.%Al2O3 increased as the heat exposure time increased. It is found that the reinforcement of alumina allowed the particles to uniformly distributed when the sample was heated for 10 hours. The formation of NiAl started when the sample was heated at 1 hour and NiAl continued to form when heated at 10 hours.