脉冲频率对7050高强铝合金微弧氧化膜层的影响

在脉冲频率为50、250、500、750、1 000 Hz的条件下，应用微弧氧化（MAO）技术在7050高强铝合金表面制备了陶瓷膜层，并采用扫描电镜（SEM）、X射线衍射仪（XRD）、电化学工作站、摩擦磨损试验机等手段分别对陶瓷膜的表面形貌、相组成、耐腐蚀性、耐磨性等进行分析。结果表明，当脉冲频率过低时，MAO陶瓷膜层表面粗糙，影响膜层致密性；而当脉冲频率过高时，则不利于MAO陶瓷膜层生长，所得的膜层耐蚀性和耐磨性较差。当脉冲频率为250 Hz时，所制备的膜层具有最佳的耐磨性及耐蚀性。

Effects of pulse frequency on MAO coatings of AA7050

The Micro-Arc Oxidation(MAO) ceramic coatings were prepared at the pulse frequencies of 50, 250, 500, 750, 1 000 Hz on the 7050 high strength aluminum alloy. To analyze the surface morphology, phase composition, corrosion resistance and wear resistance of ceramic coatings, the Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), electrochemical workstation, friction-abrasion tester were used. The results showed that when the pulse frequency was too low, the surface of MAO ceramic coating would be rough, which affected the compactness of the coating. When the pulse frequency was too high, it would be unfavorable to the growth of MAO ceramic coating, and the corrosion resistance and wear resistance of the as-prepared coatings were poor. When the pulse frequency was 250 Hz, the coating was of the best wear resistance and corrosion resistance.