EVOLUTION OF PARTICLE DIAMETERS AND PARTICLE VELOCITIES DURING LIQUID METAL ATOMIZATION

摘要

Gas atomization of liquid metal using the De Laval nozzle is one of the most efficient processes in terms of powder quality including size and composition criteria and in terms of inert gas consumption used to atomize liquid metal. However, the comprehension of the involved events is at that time of prime importance to optimize this process and the researches are focused on both experimental and modelling approaches. For example, very few experimental data are available on liquid metal atomization because of the difficulty to achieve measurements very close to the atomization area. The paper concerns some experimental results obtained with Al-5 wt. % Mn metal spraying. The evolution of the powder characteristics, i.e., particle-size distribution and particle velocity during the process were investigated. Then, some particles were collected in different samples during the atomization process and the relationship between the atomizing pressure and the resulting powder size was analyzed. The particle image velocimetry (PIV) has been used to measure the particle velocity in the atomizing chamber. The results were determined as a function of the process parameters.