The Growth Kinetic Behaviors Of The Intermetallics At W/Co Interface Under The Current Of Spark Plasma Sintering

The interdiffusion behaviors of elements at the W/Co interface under the application of current during SPS were investigated. It is found that Co7W6 and Co3W are formed at the W/Co bonding interface. The growth of the Co3W layer is apparently improved by the high current during SPS. The growth rate constant of the Co3W layer undercurrent is 1.73-3.03 times faster than that without current. The research shows that the growth rate is increased with the current density. The growth activation energy of the Co3W layer is calculated to be 229.51 +/- 27 kJ mol(-1) undercurrent, which is smaller than that without current (279.38 +/- 11 kJ mol(-1)). Moreover, the growth activation energy of the Co3W layer is decreased with the increase of the current density. The mechanism of current-improved growth of the Co3W layer is suggested to be the fact that the current lowers the nucleation barrier of intermetallic layer, which accordingly promotes chemical reactions.