Formation and Removal of Silicon Ion Deposits on Glass and Metal Surfaces

Abstract

Scale-like dirt (ion deposit) occurs on glass surfaces of buses and trains after rain or vehicle washing, as various ionic substances are in the rain and tap water. Ion deposits blur the glass, leading to degraded passenger service. Removal of ion deposits is not possible with a general cleaner. The formation behaviour of ion deposits was examined in order to develop a quick cleaning method of glass surfaces of vehicles. Ion deposits form due to silicon ions in the water. Ion deposits and glass surfaces have strong adhesion. Analysis of laser Raman spectroscopy revealed that ion deposits are mainly composed of silicon and are almost the same compound as glass. Ion deposits could be removed with a low concentration of hydrofluoric acid, and it was possible to remove about 1 mg of ion deposit by using 1 mL of 0.5% hydrofluoric acid.