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.