Electrodeposited silica films post-treated with organosilane coupling agent as the pretreatment layers of organic coating system

This work presents a new type of coating system based on the use of electrodeposited SiO2 (E-SiO2) film post-treated with (3-glycidoxypropyl)-trimethoxysilane (GPTMS) as the pretreatment layer. The silane-modified E-SiO2 films take advantage of not only the highly rough and porous features provided by E-SiO2 skeleton, but also the chemical functionalization offered by organosilane molecule. As a result, the composite pretreatment layer provides improved adhesion to the topcoat. In addition, the experimental results of electrochemical impedance spectroscopy, salt spray test, iron-dissolution measurement and the scanning vibrating electrode technique suggest that painting system constructed on GPTMS-treated E-SiO2 films exhibits excellent corrosion performance.