Scratch resistance and adherence of novel organic–inorganic hybrid coatings on metallic and non-metallic substrates

Organic–inorganic hybrid coating material with a very high level of inorganic loading was prepared by a sol–gel process in which the initial hydrolysis and condensation steps of the inorganic precursors are separated. The coating solution was deposited onto various metallic and non-metallic substrates by a simple flow coating method. The coatings were then cured using UV radiation. The adherence of this coating material was assessed by scratch testing and indentation testing, together with electron microscope observations of the coating–substrate interfaces. The coating was shown to adhere well to aluminium, nickel and glass substrates and to adhere particularly well to polyterephthlate, polycarbonate and polymethyl methacrylate substrates. By comparison, the quality of the adherence of the coating on brass and stainless steel substrates was less good.