Formation of intermetallic phases during ageing of Zn electroplate on the Cu substrate

The intermetallic phase composition and kinetics of its formation at room temperature have been investigated in thin layers of Zn electrodeposited on Cu substrates with a different microstructure. It has been determined by means of the XRD technique that three intermetallic CuZn phases: Z, e, and g appear during the ageing of thin Zn–Cu layers. The e-CuZn3 phase develops most quickly, starting to form already during zinc electrodeposition. A higher formation rate of the e-CuZn3 phase was determined for a Zn layer on the copper substrates with a higher dislocations density. A slow formation rate of the g-Cu5Zn8 phase was accounted for slower grain volume diffusion as compared to that of the grain boundary. Zinc diffusion coefficient was calculated using cyclic voltammetry data and it is equal to 1:4 10 15 cm2 s 1. # 2004 Elsevier B.V. All rights reserved