SiO_2纳米粒子对溶胶凝胶涂层性能的影响

Effect of Silica Nanoparticles on Performance of Sol-Gel Coatings

在高强钢表面制备了防护性溶胶凝胶涂层,并研究了不同浓度二氧化硅纳米粒子的加入对于涂层形貌、耐蚀性和硬度的影响。采用扫描电子显微镜(SEM)和电子能谱(EDS)观察了涂层的微观结构和成分;采用显微硬度计测试了涂层的硬度;采用电化学方法研究了二氧化硅纳米粒子的浓度对于涂层耐蚀性能的影响;采用傅里叶红外光谱研究涂层的化学结构,进而探讨了二氧化硅纳米粒子对于涂层的强化机理。结果显示涂层加入二氧化硅纳米粒子的最佳浓度为500 mg.L-1,此条件下的涂层表面均匀致密,有较高的硬度并且在3.5%NaCl溶液中体现出较好的耐蚀作用。纳米粒子在溶胶中反应形成活性羟基基团并与硅烷发生反应生成空间网状结构,从而强化涂层。

Sol-gel coatings for corrosion protection were fabricated on high strength steel 30CrMnSiA. The effect of silica nanoparticles on performance of sol-gel coatings was studied. The morphology and chemical composition of the coatings were investigated by using scanning electron microscopy （SEM） and energy dispersive spectrometry （EDS）, respectively. The hardness of the coatings was tested by using microscopic hardness meters. The corrosion resistance of the coatings was studied by electrochemical impedance spectroscopy （EIS） during immersion in 3.5% NaC1 solution. Fourier transform infrared spectroscopy （FTIR） was used to study the chemical structure of the coatings. The results demonstrate that the optimal concentration of silica nanoparticles is 500 mg-L-I, under which the coatings are of the best performance with uniform surface, dense structure, high hardness and excellent corrosion resistance. The doped silica nanoparticles generate active hydroxyl groups in the sol, form covalent bonds with the coating matrix, and thus strengthen the coatings.