An Experimental Study on Composition Characteristics of SiO$_2$/TiO$_2$/Multicomponent Particle Generated in a Coflow Diffusion Flame

Abstract

Chemical compositions of polydisperse SiO/TiOmulticomponent aggregates were measured for different heights from the burner surface and different mobility diameters of aggregates. SiO/TiOmulticomponent particles were generated in a hydrogen/oxygen coflow diffusion flame from two sets of precursors: TTIP(titanium tetraisopropoxide), TEOS(tetraethylorthosilicate). To maintain 1:1 mole ratio of TTIP:TEOS vapor, flow rate of carrier gas was fixed at 0.6lpm for TTIP, at 0.1lpm for TEOS. In-situ sampling probe was used to supply particles into DMA(differential mobility analyzer) which was calibrated with using commercial DMA(TSI, model 3071A) and classifying monodisperse multicomponent particles. Classified monodisperse particles were collected with electrophoretic collector. The distributions of composition from particles to particle were determined using EDS(energy dispersive spectrometry) coupled with TEM(transmission electron microscope). The chemical(atomic) compositions of classified monodisperse particle were obtained for different heights; z=40mm, 60mm, 80mm. The results suggested that the chemical(atomic) composition of SiOdecreased with the height from burner surface and the composition of SiOand TiOapproached to the value of 1 to 1 fat downstream. It is also found that the composition of SiOdecreases as the mobility diameter of aggregate increases.