Preparation of Molybdenum Powders by Rotating Electrode Process

Abstract

Molybdenum powders were produced by the rotating electrode process in helium atmosphere. The electrode diameter was 0.01 m and the angular velocity was 524 and 2094 rad/s, respectively. The increase of the angular velocity was followed by the decrease of mean particle size, which was 690 and 193 μm for the indicated angular velocities, respectively. The particles obtained were spherical, and their flow rate and apparent density was high. Theoretical cooling rates were calculated and were in the range 104–106 K/sec for particle diameters 800 μm — 50 μm. Typical powder solidification structure consisted of equiaxed grains and dendrites whose sizes were related to particle size.