Abstract
Electrode Induction Melting Gas Atomization (EIGA) is a crucible free technique for powder manufacturing by gas atomization. It is especially suited for reactive and high melting metals/alloys. On application of this technique a metal rod dips into an induction coil. The rod is inductively heated up and the melt drops into a gas nozzle were it is atomized. The process can be conducted ceramic-free. One aim of the present developments was an increase in melt flow rate for an improved process efficiency. For titanium rods, 60 mm in diameter, the melt flow rate has been successively increased from initially 26 kg/h to 50 kg/h. Ar has been used as atomization gas and identical atomization conditions were applied for different melt flow rates. The powder particle size distribution was found to be independent from the melt flow rates. In order to test the potential of EIGA with respect to very high melting metals, atomization experiments using niobium (melting temperature approx. 2470 °C) have been performed. Nb has been successfully atomized. Although the processing conditions are not yet fully optimized, the fine powder yield is quite high, 15 wt% < 45 m. Powder particles of all size fractions are spherical to a high degree and the tap density of 69 % is very high.
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