C.S. Che
,
J.T. Lu
,
G. Kong
,
null
,
null
,
null
,
null
,
null
,
null
金属学报(英文版)
After steel sheets (0.37wt％Si) pre-electroplated with a thin layer of pure Fe were immersed in molten zinc for various time, the change in the microstructure of the galvanized coating on the steel and the change of α-Fe/ Γ interface were studied. The EDS (energy dispersive sepectroscopy) results show that excessive silicon accumulates on the surface of the steel substrate due to the low solubility of silicon in the Γ layer after the Fe layer is depleted by the increasing growth of the compound layers. With the movement of α-Fe/ Γ interface towards the substrate by the Fe/ Zn reaction, silicon-rich α-Fe peels off from the substrate and breaks into particles. The particles, much like an inert marker in a Kirkendall effect experiment, move towards the δ layer through the Γ layer because silicon-rich α-Fe can not be adsorbed in the Γ layer. On reaching the δ/ Γ interface, the particles quickly dissolve in the δ layer, and accelerate its growth, resulting in the gradual disappearance of the Γ layer. At the same time, the normal coating is quickly changed into coatings typical of reactive steels as silicon dissolved in the δ layer soon diffuses toward the ζ layer. A similar process may happen in the initial stage of galvanizing reactive steels on a small scale, although it is hard to be observed.
关键词:
Zn coating
,
钢
,
锌镀层
,
中间化合物
冯艳
,
王日初
,
彭超群
,
王乃光
稀有金属材料与工程
采用熔炼铸造方法制备出Mg-5%Hg-1%Ga合金,在573～773 K时效不同时间,利用X射线物相检测、扫描电镜结合能谱分析第二相Mg<,3>Hg的形貌和分布,用交流阻抗法等电化学方法研究Mg<,3>Hg对Mg-5%Hg-1%Ga阳极在3.5%NaCl(质量分数)溶液中电化学性能的影响.结果表明:时效时间从15 min延长至200 h时,Mg-5%Hg-1%Ga合金中α-Mg和Mg<,3>Hg的共晶组织转变为α-Mg基体中弥散分布Mg<,3>Hg颗粒,这种转变降低了浓差极化和法拉第反应中电荷传递电阻,提高电化学活性.弥散分布的Mg<,3>Hg颗粒使Mg-5%Hg-1%Ga合金组织均匀,提高了耐腐蚀性能.
关键词:
Mg-Hg-Ga合金
,
阳极行为
,
中间化合物
,
交流阻抗
,
晶间腐蚀
