Abstract:Micro-arc oxidation (MAO) process was conducted on ZrH1.8 in an electrolyte composed of Na5P3O10 under the constant voltage mode. The influence of frequency on thickness, phase structure, cross-section morphology and the hydrogen resistance performance of coatings were investigated. The surface and cross-sectional morphologies, phase structure of the coatings and film thickness were characterized by scanning election microscopy (SEM) and X-ray diffraction (XRD). Hydrogen resistance performance was evaluated by vacuum dehydrogenation. The results show that the thickness of coatings on ZrH1.8 decreases from about 50 mm to 45 μm with the increase of frequency. The increase of frequency can enhance the density of coating effectively. Besides, the change of frequency has no obvious influence on the coating phase structure, and the coating is mainly composed of M-ZrO2 and T-ZrO1.88, and the amount of M-ZrO2 accounts for more than 80%. The increase of frequency can improve the hydrogen resistance of the ceramic coating, and the PRF (permeation reduction factor) value reaches up to 10.8 when the frequency increases to 300 Hz.