Hwang Myungwon, Chung Wonsub
Department of Materials Science and Engineering, Pusan National University, Busan 609-735, Korea.
Materials (Basel). 2018 Dec 2;11(12):2438. doi: 10.3390/ma11122438.
Plasma electrolytic oxidation (PEO) coating was obtained on AZ31 Mg alloy using a direct current in a sodium silicate-based electrolyte with and without a carbon nanotube (CNT) additive. The surface morphology and phase composition of the PEO coatings were investigated through field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The corrosion-resistance properties of the PEO coatings were evaluated using potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. Furthermore, the heat-dissipation property was evaluated by a heat-flux measurement setup using a modified steady-state method and Fourier transform infrared spectroscopy (FT-IR). The results demonstrate that, by increasing the concentration of CNT additive in the electrolyte, the micropores and cracks of the PEO coatings are greatly decreased. In addition, the anticorrosion performance of the PEO coatings that incorporated CNT for the protection of the Mg substrate was improved. Finally, the coating's heat-dissipation property was improved by the incorporation of CNT with high thermal conductivity and high thermal emissivity.
在基于硅酸钠的电解液中，使用直流电，在有和没有碳纳米管（CNT）添加剂的情况下，在AZ31镁合金上获得了等离子体电解氧化（PEO）涂层。通过场发射扫描电子显微镜（SEM）、X射线衍射（XRD）和X射线光电子能谱（XPS）研究了PEO涂层的表面形貌和相组成。在3.5 wt.%的NaCl溶液中，使用动电位极化测量和电化学阻抗谱（EIS）评估了PEO涂层的耐腐蚀性能。此外，通过使用改进的稳态方法和傅里叶变换红外光谱（FT-IR）的热通量测量装置评估了散热性能。结果表明，通过增加电解液中CNT添加剂的浓度，PEO涂层的微孔和裂纹大大减少。此外，掺入CNT以保护镁基体的PEO涂层的防腐性能得到了改善。最后，通过掺入具有高导热率和高发射率的CNT，改善了涂层的散热性能。
