SiO_(2)包覆改性铝粉的制备及对水性富铝涂料性能的影响

Preparation of SiO_(2)-coating-modified aluminum powder and its effect on properties of water-based aluminum-rich paint

以正硅酸四乙酯(TEOS)为原料,采用溶胶-凝胶法制备了应用于水性涂料体系的SiO_(2)包覆改性铝粉,通过X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、能谱(EDS)和析氢试验对改性铝粉的表面形貌、成分和在水性涂料中的稳定性进行表征,通过长期贮存试验和电化学测量技术考察了含铝粉涂层的贮存稳定性和耐蚀性。结果表明:改性铝粉表面形成了致密的SiO_(2)保护膜,而球状铝粉的包覆效果要好于片状铝粉。经50℃析氢试验100 h后,1 000目和2 000目的改性球状铝粉的析氢量较改性前下降了99%以上。以改性球状铝粉制备的水性涂料放置6个月后状态良好,其涂层与含未包覆铝粉的涂层相比具有更好的耐蚀性。

Some SiO_(2)-coating-modified aluminum powder applicable to waterborne paints was prepared with tetraethyl orthosilicate(TEOS) by sol–gel method. The surface morphology and composition of the modified aluminum powder and its stability in waterborne paint were characterized by X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), energy-dispersive spectroscopy(EDS), and hydrogen evolution test. The long-term storage stability of the paints containing the modified powder was tested and the corrosion resistance of their cured coatings were examined by electrochemical methods. The results showed that a compact SiO2film could be formed on the surface of aluminum particle,and the coverage of SiO_(2)film on spherical aluminum powder was better than that on flaky aluminum powder. After the hydrogen evolution test at 50 ℃ for 100 h, the hydrogen evolution amount of the modified aluminum spheres(1 000 mesh and 2 000 mesh in size) was reduced by more than 99% as compared with that of the unmodified aluminum spheres. After six months of storage, the waterborne paint prepared with the modified aluminum spheres was in good condition, and the coating formed therefrom had better corrosion resistance than that containing the unmodified aluminum spheres.