Effects of Si Solid Solution in Fe Substrate on the Alloying Reaction between Fe Substrate and Liquid Zn

Abstract

Effects of Si solid solution in Fe substrate on the formation of Fe-Zn intermetallic phase layers between the Fe(-Si) substrate and liquid Zn were investigated using a combinatorial technique. The formation of ζ-FeZn 13 layer was promoted by Si solid solution up to 2 at.% in the Fe substrate but retarded by further solution. The formation of δ 1 -FeZn 7-10 phase and Γ-Fe 3 Zn 10 phase was retarded by Si solid solution up to 10 at.%. The rate of Fe dissolution from the Fe substrate to the liquid Zn region and the Fe/Zn/Si contents in the δ 1 phase were analyzed as a function of Si content in the substrate. The results obtained suggest that the retardation of the Fe-Zn phase formation is caused by a difficulty in the nucleation of δ 1 phase at lower Si contents less than 3 at.% and by a decrease in the rate of Fe dissolution at higher Si contents.

Effects of Si on the formation of intermetallic phases in alloying reaction between iron substrate and liquid Zn containing 0.2 wt% Al

“…It can be seen that Si is depleted in the intermetallic phase layer. The partitioning of Si is in consistent with a recent study which reported that the Si content detected in the δ 1 and ζ phases is much lower than that in the iron substrate [7]. EBSD patterns obtained from the samples after galvanizing and annealing for 1 min at 500 °C: a, b a Γ phase pattern taken from a high Fe content region, marked by A in Fig.…”

“…Yasui et al [6] found that the retardation took place even in the absence of oxide particles, and reported that it can be explained by the solid solution of Si into the Fe-Al intermetallic phase to enhance its barrier effect and/ or the solid solution into the δ 1 phase to retard the interdiffusion between Fe and Zn through the phase. The partitioning of Si into the intermetallic phases during the alloying reaction was, however, rarely reported [7][8][9], and the effect of Si on the retardation of the alloying reaction is therefore not fully understood especially in the absence of oxide particles on the substrate/coating interface.…”

Effect of Si/Mn Ratio on Galvannealing Behavior of Si-added Steel

“…Another problem caused by Si is delay of the galvannealing reaction, but the mechanism of this phenomenon has not been clarified.Many studies have been carried out to elucidate the mechanism, and some possibilities have been proposed, such as the action of the Si-containing oxide on the steel surface or the effect of solute Si in the steel. [6][7][8][9][10][11][12][13] However, most previous studies focused on the influence of the Si content in the steel. Si is often added to steel together with Mn, which is also an attractive element for hardening steel.…”