STUDY OF THE SINTERING OF NANOSIZED TITANIA AGGLOMERATES IN FLAMES USING IN-SITU LIGHT-SCATTERING MEASUREMENTS

A premixed flame aerosol reactor was used to produce titania particles by oxidation of titanium isopropoxide vapor. The growth, aggregation of particles, and the agglomerate structure were determined as a funct ion of height in the flame using in situ light scattering and transmis sion electron microscopy (TEM) measurements. A methodology to determin e the sintering characteristic time using light scattering data was es tablished. The light scattering data provided the evolution of the fra ctal dimension which was then related to the normalized surface area c hange using a computer simulation. The sintering equation was redevelo ped in terms of the normalized surface area, thus not having to accoun t for coagulation effects. Experimental results indicate that isolated titania particles were observed at the high temperatures due to fast sintering. An agglomerate was obtained at downstream locations with an associated change in fractal dimension due to sintering. (C) 1997 Ame rican Association for Aerosol Research.