锆合金是重要的反应堆结构材料，用于燃料棒包壳和格架等元件。表面处理能够提高锆合金高温腐蚀性能，有利于提升反应堆服役安全性。本文对核级纯Zr、Zr-1Nb合金及Zr-0.39Sn-0.32Nb合金进行微弧氧化(MAO)表面处理，探测等离子体放电过程中的噪声、振动频谱和光发射谱。分析微弧氧化膜的成分、组织结构及其性能，并重点采用原位高温电化学方法研究了锆合金及微弧氧化膜在高温高压水化学环境中的腐蚀特性，同时也初步探索其在功能膜领域应用。

采用硅酸盐、磷酸盐电解液，在锆及锆合金表面制备不同厚度的微弧氧化膜，膜层主要由m-ZrO₂相和少量t-ZrO₂相组成。噪声、振动频谱与发射光谱分析发现，来自合金基体的Zr和电解液的O, H, Si, Na等元素都参与放电过程。微弧放电火花激发与淬灭过程产生冲击波，激发出水声信号和空气噪音，其反冲力引起样品振动。

为拓展锆合金微弧氧化在功能膜方面的应用，Zr-0.39Sn-0.32Nb合金在硅酸盐电解液中制备出较厚的微弧氧化膜，其在低频高温时介电常数明显增加，电导率随着频率和温度的升高而增大，低频区温度影响更明显。此外，利用微弧氧化技术在纯锆表面制备了多孔的ZrO₂/SiO₂复合薄膜，其空间结构稳定，有助于完成嵌锂与脱离过程。充放电500次循环依然稳定，高电压条件下最高充电比容量可达200 mAh/g。该复合膜在锂电池领域有较好应用前景。

研究了Zr-1Nb、Zr-0.39Sn-0.32Nb合金及其微弧氧化膜在300 ℃/14 MPa的2.3 ppm Li⁺ + 1500 ppm B³⁺ 溶液中的原位电化学腐蚀特性，评估保温时间及溶液温度对其极化曲线和电化学阻抗谱特征的影响。硼锂溶液中Zr-1Nb合金和Zr-0.39Sn-0.32Nb合金的氧化激活能分别为24.39 kJ/mol和14.41 kJ/mol。随温度升高，微弧氧化膜的腐蚀电流密度快速增加，阻抗值相应降低，其耐腐蚀性能都随着溶液温度升高而快速下降。300 ℃/14 MPa保温期间，微弧氧化膜的极化曲线和阻抗谱比Zr-1Nb和Zr-0.39Sn-0.32Nb合金基体更加稳定。锆合金及微弧氧化膜在300 ℃/14 MPa下保温700 h ~ 800 h后氧化膜主要由m-ZrO₂相组成。通过Mott-Schottky曲线分析发现，高温下生成的氧化膜具有两性氧化物的特征。微弧氧化表面处理提高了锆合金的抗高温腐蚀性能，其中致密内层起关键作用。

用热重分析模拟失水事故时包壳蒸汽氧化特性发现，Zr-0.39Sn-0.32Nb微弧氧化膜在1200℃水蒸汽中氧化增重低于锆合金基体，微弧氧化处理在一定程度上提高锆合金的抗蒸汽氧化能力。对Zr-1Nb合金激光焊接样品进行微弧氧化处理，在300 ℃/14 MPa的硼锂水溶液中保温80天后，未微弧氧化处理的焊缝区域腐蚀氧化膜明显增厚，而覆盖微弧氧化膜的焊缝和母相区腐蚀均匀，微弧氧化表面处理有利于改善包壳管的焊缝腐蚀程度。

Zirconium alloy is an important structural material for reactor, and it is widely used for fuel rod cladding and trellis. Surface treatment can improve the corrosion performance of zirconium alloy at high temperature, which is conducive to improving the safety of the reactor in service. In this paper, the nuclear grade pure Zr, Zr-1Nb alloy and Zr-0.39Sn-0.32Nb alloy were treated by micro-arc oxidation (MAO), and the acoustic, vibration and optical emission spectrum in the plasma discharge process were studied. The composition, structure and properties of MAO film were analyzed, and the corrosion characteristics of zirconium alloy and MAO film in high temperature and high pressure water in-situ chemical environment were studied by means of high temperature in-situ electrochemical method. Meanwhile, its application in the field of functional film was also explored.

In silicate and phosphate electrolyte, MAO films of different thickness were prepared on the surface of zirconium and zirconium alloys. The film was mainly composed of m-ZrO₂ phase and a small amount of t-ZrO₂ phase. The analyses of acoustics, vibration spectrum and emission spectrum showed that Zr from the alloy matrix and O, H, Si, Na from the electrolyte were involved in the discharge process. The spark excitation and quenching of micro-arc discharge produced shock wave, which stimulated the underwater acoustic signal and air noise, and the recoil force caused the sample vibration.

In order to expand the application of zirconium alloy MAO film in functional film field, thhe MAO film prepared on Zr-0.39Sn-0.32Nb alloy in silicate electrolyte had obvious increase in dielectric constant at low frequency and high temperature. The conductivity increased with the increase of frequency and temperature, and the influence of temperature in low frequency region was more obvious. In addition，porous ZrO₂/SiO₂ composite films were prepared on the surface of pure zirconium. It was found that the composite film prepared by MAO technology had stable spatial porous structure, which was conducive to the completion of lithium embedding and disengagement process. The film structure was still stable after 500 cycles of charge and discharge, and the maximum charging capacity can reach 200 mAh/g under MAO high voltage conditions. The results showed that MAO had a good application prospect in the lithium battery field.

The in-situ electrochemical corrosion characteristics of Zr-1Nb alloy, Zr-0.39Sn-0.32Nb alloy and their MAO films in 2.3 ppm Li⁺ + 1500 ppm B³⁺ solution at 300 ℃/14 MPa were studied. The effects of holding time and solution temperature on the polarization curve and electrochemical impedance spectrum were evaluated. The oxidation activation energy of Zr-1Nb alloy in boron lithium solution was 24.39 kJ/mol, and that of Zr-0.39Sn-0.32Nb alloy was 14.41 kJ/mol. With the increase of temperature, the corrosion current density of the MAO film increased rapidly and the impedance decreased correspondingly. The corrosion resistance decreased rapidly with the increase of solution temperature. During the temperature holding period at 300 ℃/14 MPa, the polarization curve and impedance spectrum of the MAO film were more stable than that of Zr-1Nb and Zr-0.39Sn-0.32Nb alloy substrates. The zirconium alloy and the MAO film were insulated at 300 ℃/14 MPa for 700 h ~ 800 h, and the oxide film was composed of m-ZrO₂ phase. Mott-Schottky analysis found that the oxide film generated at high temperature showed both n-type and p-type semiconductor properties, indicating that it had the characteristics of amphoteric oxides.The surface treatment of MAO improved the corrosion resistance of zirconium alloy at high temperature, and the dense inner layer played a key role.

Thermogravimetric analysis was used to simulate the steam oxidation characteristics of the cladding during the water loss accident. It was found that the weight gains of Zr-1Nb and Zr-0.39Sn-0.32Nb MAO films in water vapor at 1200℃ were lower than that of the zirconium alloy matrix, and thus the MAO treatment improved the steam oxidation resistance of the zirconium alloy to a certain extent. The laser welded Zr-1Nb alloy was treated by MAO. After being insulated for 80 days in boron-lithium solution at 300 ℃/14 MPa, the corrosion oxidation film in the weld area was significantly thickened. The weld and substrate covered with the MAO films were evenly corroded. The MAO surface treatment was beneficial for improving the corrosion degree of the cladding tube weld.