Pyrolysis-Induced Polymetallosiloxane Coatings for Aluminium Substrates

摘要

Inorganic amorphous polymetallosiloxane (PMS) coating films on aluminiumsubstrate were produced through the polycondensation-pyrolysis reaction mechanisms of a sol-precursor solution. The precursor solution was formed by HCl-catalysed hydrolysis of a mixture of N-(3-(triethoxysilyl)propyl-4,5-dihydroimidazole (TSPI) and M(OC3H7)n, (M = Zr, Ti and Al, n = 3 or 4). The TSPI/Zr(OC3H7)4 or Ti(OC3H7)4 precursor systems formed higher quality thin coating films, compared to the /Al(OC3H7) system. This was because of the critical formation of the polyorganosiloxane terminated by end groups containing zirconium and titanium oxides. These end groups were derived by a dechlorinating reaction between the Cl, bonded to the propyl C in organosilane, and the hydroxylated Zr or Ti compounds in the sintering stages of the film production. Good film-forming performance resulted from moderate degrees of cross-linking of metal oxides to polysiloxane chains and of the densification of metal -.-Si linkages in the pyrolysis-induced PMS network. In addition to these factors, the formation of an oxane bond at the interface between PMS and aluminium provided corrosion protection for the aluminium substrate. Pre-ceramic polymetallosiloxane coatings, Corrosion protection, Aluminum.