Abstract

Thin and dense films are required to protect aluminum flakes in waterborne coatings from corrosion while maintaining their luster. We herein report the preparation of a self-assembled SiO₂ film from tetraethoxysilane (TEOS) using acid- and alkali-catalyzed sol-gel processes. The different SiO₂ structures formed under acid and alkali catalysis assembled into a compact SiO₂ film on the aluminum flakes, imparting corrosion resistance and stability under acidic conditions. The self-assembled film obtained when the acid-catalyzed process was performed before the alkali-catalyzed process was superior to that obtained when the sequence was reversed. This film was also significantly denser than the single coatings obtained from acid or alkali catalysis alone. FTIR, XRD, BET, SEM, TG, and theoretical calculations confirmed the formation of a dense film via the self-assembly of different types of SiO₂ particles. This process may also be applicable to the formation of colored aluminum flakes via coating with other metal oxides.

摘要

需要薄而致密的薄膜来保护水性涂料中的铝片免受腐蚀，同时保持其光泽。我们在此报告了使用酸和碱催化的溶胶-凝胶工艺，由四乙氧基硅烷（TEOS）制备自组装SiO ₂膜的过程。在酸和碱催化下形成的不同SiO ₂结构组装成紧凑的SiO ₂铝片上的薄膜，在酸性条件下具有耐腐蚀性和稳定性。在碱催化过程之前进行酸催化过程获得的自组装膜优于逆序进行时获得的自组装膜。该膜还比仅由酸或碱催化获得的单个涂层致密得多。FTIR，XRD，BET，SEM，TG和理论计算证实了通过不同类型的SiO ₂颗粒的自组装形成的致密膜。该方法还可适用于通过用其他金属氧化物涂覆形成有色的铝薄片。