Enhanced growth of Mo2C formed in Mo-C diffusion couple by pulsed DC current

Abstract

The effect of pulsed DC current (current density of up to 1476 A/cm 2) on the growth of Mo2C layer formed in Mo-C system using spark plasma sintering method was investigated at temperature ranging from 1798 to 2140 K. The phase of product formed between Mo and C was identified only as Mo2C. The thickness of the Mo2C layer increased in the presence of the current, and also the growth rate was significantly enhanced with current densities. The activation energy for the growth of the product layer also decreased above current density of 600 A/cm2. When the current density was approximately 1476 A/cm2, the activation energy for growth of the product layer was calculated to be 182±4 kJ/mol in the presence of the current which was much smaller than the activation energy of 320±3 kJ/mol in the absence of the current.