CONTROL OF 'SATELLITE' PARTICLES IN GAS ATOMISATION

摘要

Gas atomised powder is considered spherical, but in fact is often far from this ideal. "Satelliting" where particles perhaps 1-20% of the diameter of a larger particle are stuck to its surface, is a common problem, and is found to get worse as finer powders are atomised. A new system which can be fitted to conventional vertical inert gas atomisers to suppress satellite formation is described and tests on a range of metals including non-ferrous and ferrous alloys show a marked reduction in satellites which leads to an increase of bulk density, both loose and tap, of as much as 15% and much improved flow properties. Obvious applications include MIM powders, pastes for electronics, and thermal spray powders, especially the finer HVOF and plasma spray powders where good flow is important.