Electrically Controlled Flame Synthesis of Nanophase TiO₂, SiO_2, and SnO₂ Powders

Abstract

Nanophase particles with precisely controlled characteristics are made by oxidation of their halide vapors in electrically assisted hydrocarbon flames using needle-shaped or plate electrodes. The particle size and crystallinity decrease with increasing field strength across the flame. The field generated by the electrodes across the flame decreases the particle residence time in the high temperature region of the flame. Furthermore, it charges the newly formed particles, resulting in electrostatic repulsion and dispersion that decreases particle growth by coagulation. Electric fields reduced the primary particle size of TiO2, the agglomerate size of SnO2, and both the agglomerate and primary size of SiO2.

Large Eddy Simulation of Titanium Dioxide Nanoparticle Formation and Growth in Turbulent Jets

“…The formation of very fine particles from vapor encompasses a large number of physical/chemical phenomena. The exact mechanisms affecting particle properties is a complex interaction of time-temperature history along with the methods of mixing (Vemury and Pratsinis 1995;Vemury et al 1997). …”

Combustion Synthesis and Characterization of Nanocrystalline Tin and Tin Oxide (SnOx, x= 0–2) Particles

“…Pratsinis and co-workers studied SnO 2 synthesis using atmospheric pressure coflow diffusion flames 25 and premixed burnerstabilized and premixed burner-nonstabilized flames. 39 For all systems, the SnO 2 particles indexed to cassiterite and were larger than those produced in the current work, with particle sizes determined from specific surface areas ranging from ϳ52 to 164 nm for the diffusion flames and from ϳ36 to 65 nm for the premixed flames.…”

Halbleitergassensoren: Trockensynthese und Anwendung

“…B. durch Sputtern, [49,78] in einem Heißwand-Aerosolreaktor [39,124] sowie durch Diffusionsflammen [125][126][127][128] und Sprayflammen mit der Zufuhr eines Gases bzw. einer Flüs-sigkeit.…”