Modified interfacial reactions in Ag-Zn multilayers under the influence of high DC currents

The influence of DC currents of up to 764 A/cm(2) on interfacial reactions in silver-zinc diffusion couples was investigated at temperatures between 300 and 350 degreesC. Regardless of current density, the product always contained three intermetallic compounds: AgZn, Ag5Zn8, and AgZn3. The relative abundance of each of the compounds was unaffected by the current. The AgZn phase was dominant, followed by the Ag5Zn8 and AgZn3 phases. The imposition of a DC current, however, was found to strongly enhance the growth kinetics of all phases above a threshold value. The threshold current increases with increased reaction temperature. The increase in growth of all phases was unaffected by the direction of the current, implying that electromigration was not a dominant cause of the enhanced growth. It is suggested that a possible current effect is an increase in defect concentration or atomic mobility. (C) 2004 Elsevier Ltd. All rights reserved.