Nanopowders Production and Micron-Sized Powders Spheroidization in DC Plasma Reactors

Technology for metal and inorganic compounds nanopowders production in DC arc plasma reactors has been developed. Similar DC arc plasma reactors were used for micron-sized powders spheroidization. Results of experimental studies are presented. Formation of nanoparticles via different mechanisms as well as mass transfer of nanopowders to the reactor cooling surfaces are discussed. Heat flux distribution along the reactor wall and its influence on the evolution of nanoparticles in the deposited layer are investigated. Effects of plasma torch and confined jet reactor operation parameters on the granulometric, phase and chemical composition of nanopowders are discussed. Potential of the confined plasma jet apparatus for micron-sized metal and composite particles spheroidization is demonstrated

Preparation of W-C-Co Composite Micropowder with Spherical Shaped Particles Using Plasma Technologies

The possibility of obtaining composite micropowders of the W-C-Co system with a spherical particle shape having a submicron/nanoscale internal structure was experimentally confirmed. In the course of work carried out, W-C-Co system nanopowders with the average particle size of approximately 50 nm were produced by plasma-chemical synthesis. This method resulted in the uniform distribution of W, Co and C among the nanoparticles of the powder in the nanometer scale range. Dense microgranules with an average size of 40 microns were obtained from the nanopowders by spray drying. The spherical micropowders with an average particle size of 20 microns were received as a result of plasma treatment of 25.36 microns microgranule fraction. The spherical particles obtained in the experiments had a predominantly dense microstructure and had no internal cavities. The influence of plasma treatment process parameters on dispersity, phase, and chemical composition of spherical micropowders and powder particles microstructure has been established