Growth of intermetallic compounds in solid Zn/Fe and Zn/Fe-Si diffusion couples

The growth of Zn-Fe intermetallic compounds and the effect of Si were studied by means of diffusion experiments at 385 ℃ for 30-300 min. The results show that the diffusion layers is mainly composed of δ phase in Zn/Fe couples, the interface between ζ and δ phases is planar, the thickness of δ phase increases and ζ phase decreases with time, dζ/dδ is zero at 300 min. In Zn/Fe-Si couple, the diffusion layers is mainly composed of ζ phase, δ phase protrudes into ζ phase in island shape, and the silicon in iron promotes the growth of ζ phase and restrains the growth of δ phase in the initial period, δ phase increases linearly with the increase of time in the later period. The growth of the total layer in three couples is diffusion-controlled.