Gao Guangrui, Li Ying, Li Chaozhong, Hu Dan, Li Zhengxian, Xi Zhengping
School of Metallurgy, Northeastern University, Shenyang 110819, China.
Research Institute of Corrosion and Protection, Northwest Institute for Nonferrous Metal Research, Xi'an 710016, China.
Materials (Basel). 2017 Nov 13;10(11):1301. doi: 10.3390/ma10111301.
Ceramic coatings with high emissivity were fabricated on TC4 alloys by micro-arc oxidation technique (MAO) in mixed silicate and phosphate electrolytes with varying KMnO₄ addition. The microstructure, phase and chemical composition were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), and the infrared emissivity of the MAO coatings was measured in a waveband of 5-20 μm. The results show that the thickness of the coatings increased with the addition of KMnO₄, but the roughness of the coatings first decreased and then increased slightly due to the inhibitory effect of KMnO₄ on Na₂SiO₃ deposition. The main phase composition of the coatings was anatase and rutile TiO₂, amorphous form of SiO₂ and MnO₂. The infrared emissivity value of the coatings strongly depended on KMnO₄ concentration, the coating formed at the concentration of 0.8 g/L KMnO₄ reached the highest and an average of up to 0.87 was observed.
通过微弧氧化技术（MAO），在含有不同添加量KMnO₄的混合硅酸盐和磷酸盐电解液中，在TC4合金上制备了具有高发射率的陶瓷涂层。采用扫描电子显微镜（SEM）、X射线衍射（XRD）和X射线光电子能谱（XPS）对涂层的微观结构、相组成和化学成分进行了表征，并在5-20μm波段测量了MAO涂层的红外发射率。结果表明，涂层厚度随KMnO₄添加量的增加而增加，但由于KMnO₄对Na₂SiO₃沉积的抑制作用，涂层粗糙度先降低后略有增加。涂层的主要相组成是锐钛矿和金红石TiO₂、非晶态SiO₂和MnO₂。涂层的红外发射率值强烈依赖于KMnO₄浓度，在KMnO₄浓度为0.8 g/L时形成的涂层发射率最高，平均可达0.87。
