The influence of gas pressure and temperature on the characteristics of aluminium powder produced by a novel low-pressure hot gas atomisation process

Abstract

A new low-pressure hot gas atomisation method exploiting the Venturi phenomenon is presented. The working gas is accelerated into a Venturi nozzle and is mixed with the molten metal that is atomised to transform to fine particles. The current work explores the case of pure aluminium that is atomised by carbon dioxide flowing through the Venturi nozzle, while the effect of operating gas temperature and pressure on the particle diameter distribution is investigated. At low temperatures, there is an almost linear relationship between the particle size and the gas pressure with a trend to produce smaller particles at higher gas pressures. This trend cannot be generalised at higher temperatures. The finer powder with average diameter d 50 of 129 µm and diametric range ΔH of 362 µm was produced at an operating gas pressure of 3 × 10 5 Pa (3 bar) and temperature of 903.15 K (630°C).