Influence of phosphorus on the growth of Fe–Zn intermetallic compound in Zn/Fe diffusion couples

Zn/Fe and Zn/Fe–P liquid–solid diffusion couples were annealed at 450 °C to investigate the effect of phosphorus in steel on the growth kinetics of Fe–Zn intermetallic compounds in diffusion zone. The results show that phosphorus in steel can delay or suppress the growth of Г phase and promote the growth of ζ phase. The higher the content of phosphorus in steel is, the faster the growth of the ζ phase is. The growth kinetics of the total layer of Fe–Zn intermediate phases in Zn/Fe–0.123 wt.%P diffusion couple is the same as that in Zn/Fe diffusion couple. But the growth behavior of Fe–Zn intermediate phases in Zn/Fe–0.340 wt.%P diffusion couple differs remarkably from that in Zn/Fe diffusion couple. The diffusion path model is introduced to explain this phenomenon.