目的 研究超音频脉冲能量对AZ31B镁合金微弧氧化膜层成膜过程、微观结构与形貌和耐腐蚀性能的影响，并分析其成膜机理。方法 通过改变超音频脉冲频率(50、100、150 kHz)调节脉冲能量，在硅酸盐体系中对AZ31B镁合金基体表面进行微弧氧化，采用激光共聚焦、SEM/EDS、XRD等对膜层表面形貌、元素组成及物相进行分析，通过电化学测试表征膜层耐腐蚀性能。结果 在硅酸盐体系中制备的微弧氧化膜层物相组成主要是MgO和Mg2SiO4。随着超音频脉冲频率提高，脉冲能量降低，微弧氧化起弧时间延长，膜层微孔尺寸减小，膜层表面均匀性提高。与基体相比，在超音频脉冲条件下制备的微弧氧化膜层，自腐蚀电位提高了1.5 V，膜层自腐蚀电流密度降低了3~4个数量级。结论 超音频电压脉冲会显著影响镁合金微弧氧化膜层微观结构，提高膜层均匀性。脉冲频率增加即脉冲能量降低，将降低微弧氧化过程中电弧的尺寸，增加电弧数量，进而降低膜层表面微孔尺寸，同时，降低表面疏松层厚度，提高致密层厚度，有利于提高膜层的耐腐蚀性能。

The work aims to study the effect of ultrasonic pulse energy on the film formation process, microstructure, morphology, and corrosion resistance of micro-arc oxidation (MAO) coatings on AZ31B magnesium alloy, to further analyze the film formation mechanism. By varying the ultrasonic pulse frequency (50, 100, 150 kHz) to adjust the pulse energy, micro-arc oxidation was performed on the surface of the AZ31B magnesium alloy substrate in a silicate system. The surface morphology, elemental composition and phase structure of the coating were analyzed by laser confocal microscopy, SEM/EDS and XRD. The corrosion resistance of the coating was characterized through electrochemical testing. The phase composition of the micro-arc oxidation coating prepared in the silicate system mainly consisted of MgO and Mg2SiO4. As the ultrasonic pulse frequency increased, the pulse energy decreased, leading to an extended arc initiation time during the MAO process, a reduction of the micropores diameter, and an improvement in the uniformity of the coating surface. Compared with the substrate, the MAO coating prepared under ultrasonic pulse conditions exhibited an increase in self-corrosion potential by 1.5 V and a reduction in self-corrosion current density by 3 to 4 orders of magnitude. In conclusion, ultrasonic pulses voltage significantly affects the microstructure of magnesium alloy MAO coatings and enhances the uniformity of the coatings. With the increase of pulse frequency, which corresponds to a decrease of pulse energy, the size of the arcs during the MAO process reduces, and the number of arcs increases. Consequently, the size and diameter of the micropores on the surface of the MAO coating are reduced. At the same time, it also reduces the thickness of the loose layer and increases the thickness of the dense layer, which is great beneficial to improve the corrosion resistance of the coatings.