Microarc oxidation (MAO) is a widely employed technology for the corrosion protection of metal surfaces due to the formation of thick-layer ceramic substances. However, its practical effectiveness is strictly limited by the inevitable concomitant generation of numerous microscale pores/cracks on the oxidation surface to directly expose the substrate materials. As concerning this problem, we here introduced a novel method of the femtosecond laser irradiation to completely eliminate the above MAO defects on aluminum alloys, which consequently modulates the passivation layer into the dense and the superhydrophobic. Meanwhile, with the deep insights into the phase composition variations of the oxide layer, we can find that the laser treatments enable the development of both γ-AlO and α-AlO nanocrystallines with embedment in the amorphous substances to significantly improve the chemical stability of materials. Such laser modifications eventually result in the ultra-corrosion-resistant surface of aluminum alloys, with the measured corrosion current density of 1.46 × 10 A/cm as well as the impedance value over 112 GΩ∙cm, about two orders of magnitude enhancement in the anticorrosion compared to the initial MAO sample.

中文翻译：

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飞秒激光实现超耐蚀铝合金彻底修复微弧氧化缺陷


微弧氧化（MAO）是一种广泛采用的技术，用于通过形成厚层陶瓷物质来防止金属表面腐蚀。然而，其实际效果受到氧化表面不可避免地伴随产生的大量微孔/裂纹以直接暴露基材材料的严格限制。针对这个问题，我们在这里介绍了一种飞秒激光照射的新方法，可以完全消除铝合金上的上述MAO缺陷，从而将钝化层调节为致密和超疏水。同时，通过深入了解氧化物层的物相组成变化，我们可以发现激光处理能够形成嵌入非晶物质中的γ-Al2O和α-Al2O纳米晶，从而显着提高材料的化学稳定性。这种激光改性最终获得了铝合金的超耐腐蚀表面，测得的腐蚀电流密度为1.46×10 A/cm，阻抗值超过112 GΩ·cm，腐蚀强度提高了约两个数量级。与初始 MAO 样品相比具有抗腐蚀性。