Effect of pulsed DC current on atomic diffusion of Nb–C diffusion couple

The effect of pulsed DC current on the atomic diffusion of an Nb–C system using Spark Plasma Sintering (SPS) was investigated. In all experiments, a current density of approximately 723 A/cm² was applied to the specimen and used in a temperature range of 1,673–1,973 K. From the results of X-ray diffraction analysis, the product phases formed between Nb and C were found to be Nb₂C and NbC. The growth of product layers significantly increased in the presence of current. However, the thickness of the product layer did not change in the current direction in the SPS. The activation energies for the formation of the Nb₂C and NbC layers were calculated to be 298 ± 4 kJ/mol and 282 ± 3 kJ/mol in the presence of current, which were similar values compared to the activation energies of 300 ± 5 kJ/mol and 285 ± 2 kJ/mol in the absence of current, respectively.