The structure, kinetics and thermodynamics of formation of unconventional fluoride conversion coating on wrought AZ61 magnesium alloy are described in this work. Fluoride conversion coating was prepared by immersion of the specimens of AZ61 magnesium alloy into Na[BF₄] molten salt at 410, 420, 430, 440 and 450 °C for 0.5, 1, 2, 4, 8, 12, 24 and 36 h. Testing methods, such as scanning electron microscopy, focused ion beam cutting and transmission electron microscopy were used for the morphology analysis, chemical composition and microstructure investigation of the fluoride conversion coating. It was found that the coating was composed of the primary MgF₂ and secondary Na[MgF₃] layer. The growth mechanism of the primary coating layer was described by the empirical kinetic method. The apparent activation energy and pre-exponential factor, estimated from the Arrhenius plot, are 82.87 kJ·mol⁻¹ and 8.22 s⁻¹, respectively. The kinetic analysis of the coating growth indicates that the process is driven by the parabolic rate law of the stationary one-dimensional diffusion at 410 °C. The Jander equation of the stationary three-dimensional diffusion describes the coating growth at higher investigated temperatures.

在这项工作中描述了在锻造的AZ61镁合金上形成非常规氟化物转化膜的结构，动力学和热力学。通过将AZ61镁合金试样在410、420、430、440和450°C下分别浸入0.5、1、2、4、8、12、24和36的Na [BF ₄ ]熔融盐中来制备氟化物转化膜H。扫描电子显微镜，聚焦离子束切割和透射电子显微镜等测试方法被用于氟化物转化膜的形态分析，化学成分和微观结构研究。发现该涂层由初级MgF ₂和次级Na [MgF ₃]层。通过经验动力学方法描述了第一涂层的生长机理。根据阿伦尼乌斯图估计的表观活化能和指数前因子分别为82.87 kJ·mol ^-1和8.22 s ^-1。涂层生长的动力学分析表明，该过程是由410°C下固定一维扩散的抛物线速率定律驱动的。静态三维扩散的Jander方程描述了在更高研究温度下的涂层生长。