G060015 減圧沸騰噴霧による火炎内ナノ粒子合成法の構築

Abstract

Flame synthesis method is commercially important because of its relative low cost, one-step process and it can be operated as continuous processes. However, a novel flame synthesis method for nanoparticles is proposed to solve several kinds of problem with vapor-to-particles and droplet-to-particles formation processes. For improving their problems, the new nanoparticle synthesis method by applying the flash boiling spray to flame synthesis method is proposed in this study. This method is expected that a uniform particle size, composition and non-agglomerated nanoparticles can be generated in high purity. In the construction of this method, it is important to control the particle nucleation and growth. The particle residence time is a significant process parameter affecting the particle nucleationand growth. Then, it is thought that ambient pressure change the particle residence time. The objective of this report was to investigate the influence of ambient pressure on the TiO_2 particle characteristic. In consequence, as the ambient pressure decrease, the primary particle diameter decrease because of the short particle residence time. And the agglomeration is inhibited by elongating mean free path due to the pressure drop. Moreover, since particle growth was carried out quickly by getting higher ambient pressure, the transformation of anatase to rutile phase was inhibited, and anatase content of product particles synthesized in higher ambient pressure was increased.