Hybrid film: a case analysis of the sol-gel technology for improved mechanical properties application.

The paper deals with the analysis of the mechanical characteristics of hybrid coating obtained through the sol-gel synthesis starting from CH3Si(OCH3)3 and C6H5Si(OCH3)3 with colloidal silica, α-Al2O3, and HNO3 as catalyst. The experimental conditions refer to a not-optimized reaction parameters trying to obtain a greater sensibility on their variations. On the base of the kinetic reaction pathway the surface morphology, analysed by SEM, the hardness, the abrasion, the film porosity and the contact angles, are interpreted. Indeed the temperature appears a relevant parameter in the control of the surface aspect and the mechanical behaviour. The roles of the colloidal silica and of the nanometric α-Al2O3 were analysed. The results demonstrate the strong enclosing of the silica particle in the hybrid polymer network. On the contrary α-Al2O3 decreases the abrasion resistance due to the lack of chemical bonds with the network.