Synthesis of copper–niobium carbide composite powder by in situ processing

The in situ formation of niobium carbide (NbC) particles was investigated during mechanical alloying process as well as subsequent heat-treatment. Initial starting powders of Cu, Nb and C were used with a composition of Cu–40 wt% Nb–10 wt% C which was corresponding to Cu–40 vol% NbC. A mixture of this powder system was milled in an argon atmosphere for four different durations, i.e., 15 h, 31 h, 42 h and 54 h. X-ray diffraction was used to verify the formation of NbC. No NbC was formed after the milling process. The in situ formation of NbC in a copper matrix only took place after heat-treatment at 900 °C. Longer milling time resulted in the formation of NbC phase with more intense X-ray diffraction peaks due to powder refinement.