| abstract |
A highly densified hybrid sol-gel formulation comprising organosilane, preferably 3-(trimethoxysilyl)propyl methacrylate (MAPTMS), and a ligand, preferably methacrylic acid. The formulation may be formed from ingredients MAPTMS, tetraethyl orthosilicate, zirconium and methacrylic acid included in the molar ratio 75:5:20:20. A method for preparing a hybrid sol-gel formulation, comprising: (a) organosilane hydrolysis to form a silane sol; (b) zirconium chelation to form a zirconium complex; (c) organosilane zirconium combination to form an Si/Zr sol; (d) hydrolysis to form a pre-final sol; and (e) formation of a final sol. Step (c) may comprise slowly adding partially hydrolysed MAPTMS to zirconate complex. Step (e) may comprise addition of tetraethyl orthosilicate to the pre-final sol to form the final sol. The formulation is intended for use as a protective coating for metal surfaces. Tetraethyl orthosilicate added in the final stages of the formulation forming process is disclosed as coating the colloidal Si/Zr particles, improving their ability to bind together and allowing a dense coating to form. |