VI.I. Molten metal atomization by inert gases: off-line and on-line metal powder characterization by PDA

摘要

Modern metal powder processing techniques have a continuous demand for decreasing the mean particle size of powders and increasing powder quality in terms of, e.g., particle surface structure and morphology. The industrial processes of gas or intert gas assisted atomization (IGA) of molten metals must therefore be optimized to yield the attemrequired high quality powders at competitive prices. In the present work it was attempted to reach this optimization by two steps: first, the search for a deeper understanding of the IGA process through detailed off-and on-line PDA measurements and, second, on-line process control by adjusting the dominant process parameter, the atomizing gas pressure, to an optimized level. It was found that a droplet velocity measurement at a single specific location inside the molten metal spray of IGA may be sufficient to characterize the mean droplet diameter of the whole spray and, hence, to pre-dict the essential characteristics of the metal powder produced.