Particle Size Distribution of SnO₂ Nano-Particles Synthesized by Pulsed Wire Discharge

Abstract

The variation in particle size distribution of SnO₂ nano-particles by the pulsed wire discharge (PWD) process has been clarified. Special attention has been paid for the influence of both synthesis conditions of ambient pressure and charging voltage on the distribution. The geometric standard deviation (σ_g) and the count mean diameter (d) were clearly influenced by these conditions. This can be summarized by means of a parameter being proportional to the plasma expansion volume. It was found that σ_g and d monotonically decreased with increasing this parameter. This tendency can be explained by the reported results of numerical simulations in which both coagulation and chemical reaction in the free molecule regime are taken into account, indicating that a relatively slow reaction rate compared to the coagulation rate broadens the particle size distribution during PWD process.