Abstract Hybrid sol-gel materials provide a favorable alternative to the use of toxic phosphate and chromate conversion coating to protect metal substrates from corrosion attack. Herein, a systematic study was performed to investigate the effect of metal oxide additives i.e niobium(V) oxide), titanium(IV) ethoxide, and zirconium(IV) propoxide on the structural and corrosion protection properties of novel hybrid sol-gel coatings applied on a mild steel (MS) surface. Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) analyses revealed the introduction of structural changes on the parent hybrid polymer upon loading it with the metal oxide additives. Moreover, the gel permeation chromatography (GPC) studies of the functionalized hybrid polymeric materials proved higher polymerization extent in these materials in comparison with the parent polymer. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests have shown that the metal oxide additives displayed; to various extents, an enhancement in the barrier properties of the base hybrid coating for a MS substrate in a 3.5 wt.% NaCl medium. Zirconium(IV) propoxide additive showed the highest corrosion resistance as compared to parent sol-gel coating or other metal oxide additives. Scanning electron microscope (SEM) analyses indicate an excellent homogeneous coverage of the functionalized coatings on the MS surface with no signs of defects, delamination, or micro cracks behaviors. The present study gains deeper insights into the interactions nature between the oxide additive and the host polymer matrix.

中文翻译：

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金属氧化物添加剂对 3.5% NaCl 介质中混合有机硅溶胶-凝胶涂层结构和阻隔性能的影响

摘要 混合溶胶-凝胶材料为使用有毒磷酸盐和铬酸盐转化涂层保护金属基材免受腐蚀提供了一种有利的替代方案。在此，系统研究了金属氧化物添加剂，即氧化铌 (V)、乙醇钛 (IV) 和丙氧基锆 (IV) 对新型混合溶胶-凝胶涂层的结构和腐蚀保护性能的影响在低碳钢 (MS) 表面上。核磁共振 (NMR) 和傅里叶变换红外 (FTIR) 分析揭示了在母体杂化聚合物上加入金属氧化物添加剂后会发生结构变化。而且，功能化杂化聚合物材料的凝胶渗透色谱 (GPC) 研究证明，与母体聚合物相比，这些材料的聚合程度更高。电化学阻抗谱 (EIS) 和动电位极化测试表明，金属氧化物添加剂显示出；在 3.5 wt.% NaCl 介质中，MS 基材的基础杂化涂层在不同程度上增强了阻隔性能。与母体溶胶-凝胶涂层或其他金属氧化物添加剂相比，丙氧化锆 (IV) 添加剂显示出最高的耐腐蚀性。扫描电子显微镜 (SEM) 分析表明，功能化涂层在 MS 表面具有出色的均匀覆盖，没有缺陷、分层或微裂纹行为的迹象。