摘要： 为了改善铝合金材料的耐腐蚀性能,本研究用正硅酸乙酯(TEOS)为主要原料,加入一定量的去离子水、KH-550和纳米SiO₂,以冰乙酸为催化剂制备溶胶。通过浸渍-提拉法和相应的处理在铝合金基体表面形成杂化涂层,通过电化学测试和扫描电镜(SEM)观察,结果表明:添加纳米SiO₂制备的涂层有效地提高了铝合金在3.5%NaCl溶液中的防腐性能,使铝合金基体的耐腐蚀性能和稳定性得到大幅度的提高。涂层中的纳米SiO₂含量和热处理温度对涂覆铝合金的耐蚀性能有不同影响,当纳米SiO₂含量为0.1%、热处理温度为130℃时,制备的杂化涂层性能最佳,在3.5%NaCl溶液中的腐蚀电流密度约为3.613×10^-7 A/cm²,这一数值相对于铝合金基体的腐蚀电流密度4.208×10^-5 A/cm²降低了2个数量级,显示出涂层对铝合金基体具有较好的防护效果。

关键词: 纳米氧化硅, 溶胶-凝胶, 耐腐蚀性, 杂化涂层

Abstract: To improve the corrosion resistance of aluminum alloy, a kind of sol-gel coatings was prepared from TEOS as the main component in addition to H₂O, KH-550, and Nano-SiO₂ particles. HAc was used as catalyst for sol-gel process. Dip-coating techniques was applied to form a hybrid coatings on Alalloy substrate. Electrochemical techniques and Scanning Electron Microscopy(SEM) were used to characterize the characteristics of hybrid coatings. The results showed that the Nano-SiO₂-containing hybrid coatings can improve the corrosion resistance of aluminum alloys in 3. 5% NaCl effectively, and provide effective protection for aluminum alloy substrates and greatly improve their stability. When 0. 1% of Nano-SiO₂ was addied and heat treatement temperature was 130 ℃, the corrosion current density of the sample was estimated 3.613×10^-7 A/cm² in 3. 5% NaCl solution, which was two orders of magnitude lower compared with the corrosion current density of bared aluminium alloys. This indicated a good protection for aluminium alloys by hybrid coatings.

Key words: nano-silica, sol-gel process, corrosion protection, hybrid coatings