Ultrafine Refractory Particle Formation in Counterflow Diffusion Flames
- 1 March 1992
- journal article
- research article
- Published by Taylor & Francis in Combustion Science and Technology
- Vol. 82 (1-6), 169-183
- https://doi.org/10.1080/00102209208951818
Abstract
The effect of process variables (percursor concentration, residence time, temperature, and electric field) on ceramic powder formation was studied using a counterflow diffusion dame burner. GeCl4 and SiCl4 were used as source materials for the formation of Ge02 and Si02 in hydrogen—oxygen flames. In-situ particle size and number density were determined using dynamic light scattering and 90° light scattering. A thermophoretic sampling method also was used to collect particles directly onto carbon coaled grids, and their size and morphology examined using transmission electron microscopy. Increasing the precursor concentration caused larger particles to form and enhanced surface growth effects; decreasing residence time favored homogeneous nucleation as the particle formation route; using higher temperatures resulted in a larger size for the fundamental particles but less aggregation. Using GeCl, in the presence of a 1250V/cm electric field, a three fold increase in particle size was obtained. Process variables also determined the degree of crystallinity; crystalline particles were usually found when mostly small particles were produced; amorphous particles were found when high precursor concentration, long residence time, and low temperatures were used. These results show how desired particle characteristics (particle size, particle morphology, crystalline or amorphous) can be generated through control of flame conditions.Keywords
This publication has 20 references indexed in Scilit:
- Morphological Description of Flame-Generated MaterialsCombustion Science and Technology, 1990
- Particle sizing in combustion systems using scattered laser lightJournal of Quantitative Spectroscopy and Radiative Transfer, 1988
- Morphology of flame-generated soot as determined by thermophoretic samplingLangmuir, 1987
- The counterflow diffusion flame burner: A new tool for the study of the nucleation of refractory compoundsCombustion and Flame, 1985
- Determinations of turbulent velocity fluctuations and mean particle radii in flames using scattered laser-power spectraJournal of Quantitative Spectroscopy and Radiative Transfer, 1981
- Basic research needs on high temperature ceramics for energy applicationsMaterials Science and Engineering, 1980
- Deposition Properties of SiO2-GeO2Particles in the Flame Hydrolysis Reaction for Optical Fiber FabricationJapanese Journal of Applied Physics, 1980
- Aerosol measurement by laser doppler spectroscopy—I. Theory and experimental results for aerosols homogeneousJournal of Aerosol Science, 1972
- The ultraviolet bands of OH Fundamental dataJournal of Quantitative Spectroscopy and Radiative Transfer, 1962
- Spectral Absorption Method for Determining Population “Temperatures” in Hot Gases*†Journal of the Optical Society of America, 1956