PARTICLE-SIZE CONTROL OF TIO2 ULTRAFINE PARTICLES BY CVD METHOD

Ultrafine particles of titanium dioxide were obtained in the hydrolysis of titanium tetraisopropoxide by CVD (chemical vapor deposition) method. This particle size distribution was shown to be a log normal distribution and was determined by the frequency of Brownian coagulation collisions. To find out exactly the region where the primary particles are growning, for the purpose of particle size control, a method of simulation of fluid flow which includes chemical reaction kinetics was described. It was observed that the flame which indicates the chemical reaction surface was the growth zone of the primary particles. It was concluded that the flame was an important factor in controlling the particle size distribution. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.