恒压模式下电源频率对ZrH1.8表面微弧氧化陶瓷层的影响

Effect of Frequency on MAO Film on the Surface of ZrH1.8 under Constant-Voltage Mode

摘要:

在磷酸盐体系下，采用恒压模式对氢化锆(ZrH1.8)进行微弧氧化。考察了电源频率对氧化膜的厚度、相结构、截面形貌以及阻氢性能的影响。利用扫描电镜(SEM)、X射线衍射(XRD)、膜层测厚仪分析了氧化膜的表面形貌、截面形貌、相结构及膜层厚度。通过真空脱氢实验评估膜层的阻氢性能。结果表明：随着电源频率的增加，ZrH1.8表面微弧氧化膜层厚度由约50 μm仅减小至约45 μm；电源频率的增加能有效提高膜层的致密性；电源频率的改变对于膜层的相结构没有明显影响，膜层主要由单斜相氧化锆(M-ZrO2)和四方相氧化锆(T-ZrO1.88)构成，其中单斜相占80%以上；电源频率的增加有助于提高氧化膜的阻氢效果，当电源频率增加到300 Hz时，氧化膜的氢渗透降低因子PRF值高达10.8。

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.