抄録
TiO2 -coated hollow volcanic glass spheres (Shirasu-balloons) were developed by a thermal decomposition method of hydrolytic polymers from tetra-n-butoxy titanium, and their properties were investigated. Hollow volcanic glass spheres of above 100 μm were coated with titania hydrate formed by a moistening process by steam Ti (OCH2 CH2 CH2 CH3 )4 during heating at 95 °C for 40 minutes. After drying at 120 °C in air for 12 hours, these coated spheres were performed by heat treatment for 2 hours in air at temperature ranges of 400 ∼ 1,100 °C for the purpose of controlling of crystal structure from anatase to rutile.The tetra-n-butoxy titanium could be transformed very easily into titania hydrate by using the moistening process using steam. The crystal structure formed in temperature range from 400 to 800 °C was anatase. With increasing the temperature of above 800 °C, the anatase structure was transformed into rutile and then completed only rutile at 1,100 °C. SEM analysis of the surface before and after heat treatment revealed homogeneous coating layers with TiO2 .
