Abstract
Iron-electrodeposited zinc diffusion couples were annealed at temperatures from 240 to 360°C at various compressive stresses. In the diffusion zone, intermetallic compounds appeared in the order of the ζ, δ1 and Γ phases. The thickness of the initial ζ phase layers which exist as a singl phase in the diffusion zone increases with increase in compressive stress up to 20 kg/cm2, remaining constant above this stress. The growth of the initial ζ phase layers at 50 kg/cm2 follows a parabolic rate law governing diffusion control. The temperature dependence of diffusion coefficients in the ζ phase layers was given by the following equation:
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oindentThe equation is nearly equal to that estimated by our previous study which was carried out by the use of clamps.
Kirkendall porosities develop at the interface between the ζ and zinc phases and restrict the transfer of atoms from zinc into the diffusion zone. The effect of compressive stress in the Fe-Zn system is to increase the growth rate of diffusion layers by decreasing the Kirkendall porosity.
