目的 研究微弧氧化表面处理对纯锆高温蒸汽氧化行为影响。方法 采用微弧氧化技术(MAO)在磷酸盐电解液中纯锆表面制备厚约2.5 μm的陶瓷膜，再利用热重分析仪(TGA)测量它们在1000~1200 ℃蒸汽环境中的氧化性能，并分析蒸汽氧化前后氧化膜的微观结构、物相组成。用辉光放电谱仪(GDOES)分析蒸汽氧化前后锆基体及微弧氧化样品Zr、O、P、Na、C、H元素的成分深度分布。结果 锆基体及微弧氧化膜加速氧化动力学转变温度约为600 ℃。在1000 ℃蒸汽中，微弧氧化处理的纯锆样品氧化增重低于锆基体。蒸汽温度达到1100 ℃以上时，锆基体和微弧氧化膜的氧化增重曲线几乎重合。蒸汽氧化初期氧原子快速扩散至β-Zr中，当较厚α-Zr(O)层和ZrO2层形成后，氧化速率主要取决于氧在α-Zr(O)层中的扩散速率，而且氧化锆层阻挡了氢扩散进入锆基体。高温蒸汽氧化后，纯锆表面氧化层主要由单斜氧化锆(M-ZrO2)相和少量的四方氧化锆(T-ZrO2)相组成。结论 在1000 ℃以下，微弧氧化膜增强了锆基体的抗蒸汽氧化能力，但1100 ℃以上没有保护作用。

The work aimed to study the effect of microarc oxidation (MAO) surface treatment on the high temperature steam oxidation behavior of pure zirconium. The oxidation resistance of pure Zr with and without a MAO ceramic coating of about 2.5 μm thick in 1000~1200 ℃ steam environment was evaluated by a thermogravimetric analyzer (TGA). The microstructures and phase components of bare and MAO-coated Zr before and after steam oxidation were analyzed. Their composition depth profiles of Zr, O, P, Na, C, and H elements before and after steam oxidation test were carried out by glow discharge optical emission spectroscopy (GDOES). It was found that their kinetic transition temperature for accelerated oxidation was about 600 ℃ in water vapor environment. The mass gain of MAO-coated pure Zr was lower than that of bare Zr after 3600 s steam oxidation at 1000 ℃, however, their oxidation kinetics curves almost overlapped at 1100 ℃ and 1200 ℃. In the initial stage of steam oxidation, oxygen atoms diffused rapidly into β-Zr substrate. When the thick α-Zr(O) layer and ZrO2 layer were formed, the oxidation rate of bare and MAO-coated Zr was mainly governed by the oxygen diffusion rate in α-Zr(O) layer. Furthermore, the zirconia layer prevented from hydrogen pickup into Zr substrate. After high temperature steam oxidation, the oxide layers of both bare and MAO coated pure Zr consisted of monoclinic zirconia (M-ZrO2) and a little tetragonal zirconia (T-ZrO2) phases. The MAO coating enhanced the steam oxidation resistance of pure Zr below 1000 ℃, but not above 1100 ℃.