| Abstract: | Aqueous solutions prepared from γ-glycidoxypropyltrimethoxysilane (γ-GPS) and 1,2-bis(trimethoxysilyl)ethane (BTSE) silane were used to treat Al2024-T3-clad aluminium alloy. Both fresh and naturally-aged organosilane chemicals were used to prepare the aqueous solutions. X-ray photoelectron spectroscopy and reflection absorption infrared spectroscopy were used to characterise the films produced on the aluminium substrates. The organosilane films were also rinsed in water and chloroform and reanalysed to further assess their chemical composition. Aqueous solutions prepared using fresh silane produced films that had a higher concentration of silanol groups. Silanol groups could be removed from the films by rinsing with water; however, after heating in a vacuum oven the formation of siloxane groups produced films that were insoluble in both water and chloroform. Films prepared from solutions that used naturally aged organosilane, which had been stored in a laboratory environment for five years, were thicker and contained high concentrations of methoxy groups that produced a hydrophobic layer that was soluble in chloroform. After vacuum oven drying, the films prepared using naturally-aged γ-GPS appeared to cross-link, making the films insoluble in both water and chloroform. In contrast, the film prepared using naturally aged BTSE remained soluble in chloroform after oven drying. |
