Effect of Titania Nano-Fillers on the Fracture Toughness and Mechanical Performance of Hybrid Sol-Gel Coatings

摘要

Organically modified silicates (Ormosils) are widely utilized as protective coatings due to their excellent mechanical properties and tailorable coating compositions. This paper reports the fracture toughness of 3-Glycidoxypropyltrimethoxysilane (GLYMO) and tetraethylorthosilicate (TEOS) sol-gel coatings with different amount of TiO2 nano-fillers. The critical stress intensity factor, KIc, was obtained through failure strain measurement using a controlled buckling test. The hardness, elastic modulus, together with the pencil scratch and micro sand erosion resistances of the coatings were also reported and discussed. It was found that the fracture toughness, hardness, elastic modulus are generally improved with the incorporation of TiO2 nano-fillers. The scratch and erosion resistances of the coatings are comparable with the one without fillers or even improved for high amount of nano-filler loadings. The current work provides an easy and practical route for further enhancement of the mechanical properties of Ormosil sol-gel coatings.