目的 研究原位蒸汽法制备层状双金属氢氧化物(LDH)的反应机理，以及添加Al(NO3)3对AZ91D镁合金表面水滑石蒸汽涂层耐蚀性的影响和耐蚀机理。方法 在蒸汽源中添加不同浓度的Al(NO3)3，以提供Al³⁺，采用原位蒸汽法在150 ℃下进行5 h水热反应，在AZ91D镁合金表面制备水滑石蒸汽涂层。使用XRD、FT-IR、SEM、EDS 等测试手段对水滑石蒸汽涂层进行表征，通过动电位极化、电化学阻抗和盐雾试验，研究水滑石蒸汽涂层的生长机理及腐蚀机理。结果 基于不同浓度梯度的Al(NO3)3，在AZ91D镁合金表面成功制备了水滑石蒸汽涂层，涂层的主要组成物相为Mg(OH)2、Mg-Al-NO3^?LDH、Mg-Al-CO3^2?LDH。Al(NO3)3/LDH相较于未添加Al(NO3)3得到的LDH，其生长均匀、结构致密，耐腐蚀性能由大到小的顺序为LDH-100、LDH-200、LDH-50、LDH-20、LDH、AZ91D镁合金。水滑石蒸汽涂层的腐蚀产物主要为Mg(OH)2、MgCO3。结论 在添加100 mmol/L的Al(NO3)3作为蒸汽源时，充足的Al³⁺保证了合成结构致密水滑石的需要，副产物最少，且耐蚀性最好。最后，讨论了水滑石蒸汽涂层的生长机理和腐蚀机理。

Magnesium and its alloys, due to their remarkable biodegradability and mechanical properties, particularly their specific strength, have gained widespread attention and are being increasingly utilized as a green engineering material. However, their reactive chemical nature makes them susceptible to corrosion, limiting their widespread application. Surface modification techniques now serve as an effective means of enhancing the corrosion resistance of magnesium alloys. Layered double hydroxide (LDH), a layered structural material, has the ability to adsorb corrosive ions, thus protecting the magnesium alloy substrate. Reports indicate that the Al content in magnesium alloys can affect the LDH content in steam coatings, which in turn affects the corrosion resistance of these coatings. However, the impact of introducing Al outside the magnesium alloy substrate on corrosion resistance remains unclear.