1985 Volume 3 Issue 1 Pages 68-73
A production technique of Ultra-fine Particles (UFP) has been investiagted to achieve a high genera tion rate of UFP. Ultra-fine Ni, Fe and Ti particles were generated in the Hydrogen-Argon mixed gas atmosphere at various current between Tungsten electrode and the bulk metal, and the generationrate of the UFP were measured.
It is found that the shape of arc is changed by increasing the arc current abruptly and the generation rate of UFP is drastically reduced at the particular arc curret (transiticn current).
At the lower arc current than the transition current the arc is concentrated on the anode spot, and the generation rate of UFP is very high. At the higher arc current than the transition current, the arc spreads on the bulk metal, and the genreation rate is very small.
This transition current changes, depending on a concentration of hydrogen in atmcspher, arc length and a kind of bulk metal.