Formation and growth behavior of intermetallic compound phases in the interfacial reaction of solid Fe / liquid Zn at 450?°C
Formation and growth behavior of intermetallic compound phases in the interfacial reaction of solid Fe / liquid Zn at 450?°C
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450℃固Fe/液Zn界面反应中金属间化合物相的形成和生长行为
DOI：
10.1016/j.jallcom.2021.161562
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发表时间：
2021
影响因子：
6.2
通讯作者：
Kainuma Ryosuke
中科院分区：
文献类型：
--
作者：
Han Kwangsik;Lee Inho;Ohnuma Ikuo;Kainuma Ryosuke
研究了450℃热浸镀金属间化合物(IMC)层在固态铁与熔融锌界面反应中的形成与生长行为。在界面反应的早期阶段，形成了Γ-Fe4Zn9、δ1k-FeZn7和ζ-FeZn13相，其中ζ层的生长占主导地位。在约90℃的S温度下，δ1k/δ界面上形成了ζ1p-Fe13ZN126相的柱状结构，四层IMC层同时生长到600年S。随后，沿Γ1k界面形成了一层Γ/δ1-Fe21.2Zn80.8相并开始生长，此后Γ/Γ1/δ1k/δ1p/ζ的所有平衡IMC相都竞争生长。5层IMC的总厚度d合计与反应时间的平方根t成正比增长，即d合计=d0 t0.5，表明整个IMC层的生长受体扩散控制。然而，在平衡或非平衡条件下，各IMC层的时间指数n的值因其微观结构和化学浓度而不同。多层柱状ζ相的形成可归因于界面反应早期在柱状ζ/液态锌界面附近的液态锌中Fe的非均相过饱和。根据测量的各相的浓度分布，估算了铁和锌在ϕ相(ϕ=Γ，δ1K和ζ)中的互扩散通量J。这表明，J-̃ϕ导致了各相的生长以及界面附近Fe的过饱和，从而导致了对平衡浓度的较大偏离。在界面反应后期，随着J̃ϕ的减小，界面浓度逐渐接近平衡浓度。
In the present study, the formation and growth behaviors of intermetallic compound (IMC) layers in the interfacial reaction of solid Fe and molten Zn during hot dipping at 450° C were investigated. In the early stage of the interfacial reaction, Γ-Fe 4 Zn 9, δ 1k-FeZn 7, and ζ-FeZn 13 phases were formed, among which the growth of the ζ layer was dominant. Columns of the δ 1p-Fe 13 Zn 126 phase were formed on the δ 1k/ζ interface at approximately 90 s, and the four IMC layers grew simultaneously until 600 s. Subsequently, a layer of the Γ 1-Fe 21.2 Zn 80.8 phase was formed along the Γ/δ 1k interface and started growing, after which all the equilibrium IMC phases of Γ/Γ 1/δ 1k/δ 1p/ζ grew competitively. The total thickness of the five IMC layers, d total, increased proportionally with the square root of the reaction time, t, ie, d total= d 0 t 0.5, which suggested that the growth of the entire IMC layers was controlled by the volume diffusion. However, the values of the time exponent, n, for the individual IMC layers differed depending on their microstructures and chemical concentrations, under equilibrium or nonequilibrium conditions. The formation of the multilayered columnar ζ phase can be attributed to the heterogeneous supersaturation of Fe in the liquid Zn near the columnar ζ/liquid Zn interface during the early stage of the interfacial reaction. The interdiffusion fluxes, J ̃ ϕ, of Fe and Zn in the ϕ phase (ϕ= Γ, δ 1k, and ζ) were estimated from the measured concentration profiles of each phase. This suggested that J ̃ ϕ caused the growth of each phase as well as the supersaturation of Fe near the interfacial boundaries, thereby resulting in considerable deviations from the equilibrium concentrations. In the later stage of the interfacial reaction, the interfacial concentrations gradually approached the equilibrium concentrations with decreasing J ̃ ϕ.