目的 研究锆合金微弧氧化膜的介电性能随温度的变化规律，了解?100~250 ℃范围内它们的介电频谱特性。方法 采用恒压模式的双极性微弧氧化脉冲电源，在硅酸盐电解液中对Zr-0.39Sn-0.32Nb合金进行微弧氧化处理，用扫描电子显微镜(SEM)、X射线衍射仪(XRD)及激光拉曼光谱仪(Raman)，分析微弧氧化陶瓷膜的形貌和相组成。采用变温介电谱仪测量?100~250 ℃范围内不同厚度微弧氧化膜的介电常数、介电损耗以及电导率随环境温度变化的频谱图(0.01 Hz~1 MHz)。结果 Zr-0.39Sn-0.32Nb合金表面制备出20~45 μm厚的微弧氧化陶瓷膜，它们都由m-ZrO2单斜相和少量t-ZrO2四方相组成。微弧氧化膜的致密内层对其介电特性影响较大，多孔外层降低其绝缘性能。在?100~250 ℃范围内，微弧氧化膜的低频区介电常数、介电损耗、电导率均随着温度的增加而快速增加，而温度对它们在高频区的影响较小。同时，在0~100 ℃范围内，锆合金微弧氧化膜介电性能稳定。在50 Hz工频和20 ℃环境中，微弧氧化膜的导电率约为10^?12 S/m。结论 环境温度对锆合金微弧氧化陶瓷膜介电特性有较大影响，特别在低频区变化显著。

Change rule of dielectric properties on environment temperature for microarc oxidation (MAO) coatings on Zr alloy was investigated, and their dielectric frequency spectra in range of ?100~250 ℃ were understood. A bipolar MAO pulse power supply in constant voltage mode is used to conduct MAO treatment on Zr-0.39Sn-0.32Nb alloy in silicate electrolyte. The morphologies and phase compositions of MAO ceramic coatings were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and laser Raman spectrum. A variable-temperature dielectric spectrometer was used to measure the dielectric constant, dielectric loss, and the frequency spectrum (0.01 Hz~1 MHz) of the micro-arc oxide coatings with different thicknesses in the range of ?100~250 ℃ The 20~45 μm thickness micro-arc oxidation ceramic coatings prepared on the surface of Zr-0.39Sn-0.32Nb alloy consisted of monoclinic zirconia (m-ZrO2) and a little tetragonal zirconia (t-ZrO2). The compact inner layer of MAO coatings played a key role on their dielectric property, and the porous outer layer reduced their insulating property. In the temperature range of ?100~250 ℃, the dielectric constant, dielectric loss and conductivity of MAO coatings increased rapidly with the increase of temperature in low frequency zone, but the temperature hardly affected their dielectric property in high frequency zone. Meanwhile, the dielectric property of MAO coatings of Zr alloy at 0~100 ℃ kept stable. Their conductivity was about 10?12 S/m at 50 Hz and 20 ℃. Hence, the environment temperature had a great influence on dielectric property of MAO ceramic coatings on Zr alloys, especially in low frequency zone.