本发明涉及一种热浸镀锌铝镁合金镀层及其制备方法，属于金属镀层技术领域，解决了现有溶剂法工艺在钢结构上热浸镀锌铝镁镀层工艺适应性差、镀层质量差的问题。本发明的热浸镀锌铝镁合金镀层按照质量百分比计为：Al：3～13％；Mg：0 .8～3％；其余为Zn及不可避免的杂质。制备方法包括，步骤S1：制备热浸镀所需的锌镀液及锌铝镁合金镀液；步骤S2：对钢结构进行除油处理、酸洗处理和熔剂助镀；步骤S3：将熔剂助镀的钢结构置入步骤S1制备的锌镀液中，进行热浸镀锌处理；步骤S4：将热浸镀有锌镀层的钢结构置入步骤S1制备的锌铝镁合金镀液中，进行热浸镀锌铝镁处理。本发明应用于钢结构，且镀层质量好、耐蚀性高。

The invention relates to a hot-dip galvanizing zinc-aluminum-magnesium alloy coating and a preparation method thereof, belongs to the technical field of metal coatings and aims at solving the problems of poor process adaptability and poor coating quality of a hot-dip galvanizing zinc-aluminum-magnesium alloy coating on a steel structure by using an existing solvent method process. The hot-dip galvanized zinc-aluminum-magnesium alloy coating is prepared from the following components in percentage by mass: 3-13 percent of Al, 0.8-3 percent of Mg and the balance of Zn and inevitable impurities. The preparation method comprises the following steps of: S1, preparing a zinc plating solution and a zinc-aluminum-magnesium alloy plating solution required by hot dipping; S2, conducting oil removal treatment, acid pickling treatment and flux plating assisting on a steel structure; S3, putting the steel structure subjected to flux-assisted plating in the zinc plating solution prepared in the step S1, and conducting hot-dip galvanizing treatment; and S4, putting the steel structure hot-dipped with the zinc plating layer in the zinc-aluminum-magnesium alloy plating solution prepared in the step S1, and conducting hot-dipping zinc-aluminum-magnesium plating treatment. The hot-dip galvanizing zinc-aluminum-magnesium alloy coating is applied to the steel structure, good in quality and high in corrosion resistance.