Abstract
Recently, titanium dioxide (TiO_2) attracts a great deal of attention as a photocatalyst. When ultraviolet right is irradiated, ultra-hydrophile property, that is the contact angle under 5 degrees between water and substrate, occurred. In this study, the friction property of titanium dioxide photocatalyst under ultraviolet irradiation was investigated. TiO_2 coated on a glass plane was rubbed against a glass lens in dry sliding and in water lubrication under ultraviolet irradiation. The coefficient of friction between TiO_2 coat and glass lens with water without ultraviolet irradiation was higher than that of dry sliding. The coefficient of friction at water lubrication with ultraviolet irradiation became lower than that of without ultraviolet irradiation and decreased with increasing the irradiation time. The reduction rate deduced as the irradiation time increased. The influence of ultraviolet irradiation continued for tens hours since the coefficient of friction showed a slight decrease.
