1994 Volume 31 Issue 12 Pages 862-868
A highly efficient generation process for ultra fine particles (UFP) is developed by using an arc discharge method combined with a tilting tip assembly. The arc is generated between a tungsten cathode and a bulk metal anode in an argon-hydrogen gas atmosphere. The amount of the particles generated is assumed to be the decrease in bulk metal weight.
This new process achieves a highly efficient generation rate by tilting the electrode to a particular angle, which induces the following phenomena: a concentrated anode spot caused by the thermal pinch effect of hydrogen gas, a blown arc by electromagnetic force with current electrification channel change, reaction heat caused by the thermal combination of hydrogen gas, and a plasma stream on the bulk metal surface. All of these enhance the production rate.
The generation rate of Ni UFP at a 45° electrode angle, Ar+50%H2 and 200A current is 50g/h, is about 10 times higher than that of the conventional process.
