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采用恒压模式分别在不同浓度Na2SiO3电解液体系下对ZrH1.8表面进行微弧氧化处理,利用X射线衍射(XRD)仪、扫描电子显微镜(SEM)、膜层测厚仪测试了陶瓷层的相结构、表面形貌、截面形貌及厚度,通过真空脱氢实验评估了陶瓷层的阻氢性能。研究结果表明:当Na2SiO3浓度在6~14 g/L变化时,陶瓷层的厚度在25~61μm范围内。随着Na2SiO3浓度的增加,电解液的电导率线性增大,微弧氧化陶瓷层厚度逐渐减小。氢化锆表面微弧氧化陶瓷层由致密层和疏松层构成,靠近基体一侧为致密层,陶瓷层外层为疏松层,在疏松层中存在空洞和裂纹缺陷。陶瓷层由单斜相氧化锆(M-ZrO2)和四方相氧化锆(T-ZrO1.88)构成,且以单斜相氧化锆(M-Zr O2)为主,随着电解液中Na2SiO3浓度的增加,四方相T-ZrO1.88在陶瓷层中比例增大。综合比较,在Na2SiO3浓度为8 g/L的电解液体系下可以获得厚度适中,表面平整,致密性较好,阻氢性能优异的陶瓷层,陶瓷层的PRF值达到最大值10.8。
The surface of ZrH1.8 was treated by micro-arc oxidation under different concentrations of Na2SiO3 electrolyte solution in constant voltage mode. The ceramic coatings were tested by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thickness gauge Phase structure, surface morphology, cross-sectional morphology and thickness, hydrogen resistance of ceramic layer was evaluated by vacuum dehydrogenation experiments. The results show that when the concentration of Na2SiO3 varies from 6 to 14 g / L, the thickness of ceramic layer is in the range of 25 ~ 61μm. With the increase of Na2SiO3 concentration, the conductivity of electrolyte increases linearly and the thickness of MAO layer decreases gradually. The micro-arc oxidation ceramic layer on the surface of zirconium hydride ceramic consists of a dense layer and a loose layer, with a dense layer near one side of the substrate. The outer layer of the ceramic layer is a loose layer. There are cavities and crack defects in the loose layer. The ceramic layer consists of monoclinic phase zirconia (M-ZrO2) and tetragonal phase zirconia (T-ZrO1.88), and is dominated by monoclinic zirconia (M-ZrO2). With the concentration of Na2SiO3 in the electrolyte The proportion of tetragonal T-ZrO1.88 in the ceramic layer increases. In a comprehensive comparison, the ceramic layer with moderate thickness, smooth surface, better compactness and excellent hydrogen barrier property can be obtained under the electrolyte system with Na2SiO3 concentration of 8 g / L. The PRF value of the ceramic layer reaches a maximum value of 10.8.