BH390钢热镀锌抑制层及其合金化镀层界面结构

Formation and interface structure of inhibition layers in hot-dip galvanized coating on steel BH390

利用SEM和TEM研究了铝含量不同的热镀锌镀层中抑制层的结构及抑制层在形成和生长过程中Zn-Fe-Al金属间化合物之间的反应过程;分析了铝含量不同的镀层合金化后镀层与BH390钢基体之间的界面结构。结果表明,随着锌液中铝含量的增加,镀层中抑制层的结构逐渐由晶粒粗大且不连续的Fe2Al5转变为晶粒细小相对致密的FeAl3。铝含量不同的热镀锌镀层在合金化过程中抑制层结构的变化和镀层中各相的形成及生长过程是不相同。随着锌液中铝含量的增加合金化镀层与钢基体界面结合处镀层结构的均匀性逐渐降低,在相同的合金化工艺条件下,随着锌液中铝含量的增加镀层的合金化时间延长。

Structure of inhibition layers in the hot-dip galvanized coating prepared in bath with different aluminum contents on a bake-hardening high strength steel BH390 and the formation process of the inhibition layers were studied by SEM and TEM.The interface structure between the coating and steel substrate were also analyzed after the hot-dip galvanized coatings were galvannealed.Results show that the structure of the inhibition layer transformed to FeAl3 with fine grains and relative dense structure from Fe2Al5 with coarse grains gradually with the increase of aluminum contents in the zinc bath.Different formation process of the inhibition layers was observed for different zinc-aluminum bath during galvannealing of the hot-dip galvanized coatings.The homogeneity of the coating structure gradually decreased at the interface of the galvannealed coating and the steel substrate with the increase of aluminum content in the zinc bath,and the galvannealing time of the coating increased with increasing aluminum content in the zinc bath at the same galvannealing conditions.