Influence of electric current on interdiffusion kinetics of W-Ti system during spark plasma sintering

The effect of electric current on the atomic diffusion of W-Ti system using spark plasma sintering (SPS) was investigated. The interdiffusion coefficient of W-Ti system during SPS was observed to be higher compared to that in the traditional sintering. The electromigration effect was observed in W-Ti system and an improved kinetics model was applied to reveal the role of electric current in atomic diffusion kinetics. It was found that the interdiffusion coefficient increased with increasing current density, while the activation energies were constant. This phenomenon is mainly because the atomic moving velocity is accelerated by the electron wind force in the direction of electron flow, but the diffusion mechanism remains unchanged, resulting in the invariability of activation energy of binary substitution-diffusion. Additionally, the interdiffusion coefficient is independent of the pulse pattern but strongly relies on the effective current density, implying the main acceleration mechanism of pulse current remains to be electromigration.