High frequency (HF) thermal plasma with high processing temperature (up to 10000 K) in the flame zone and fast quenching rate (105?106 K/s) at the flame tail is one of the most important methods to prepare special powders. In addition, thermal plasma is a powerful tool for synthesizing well-dispersed powders in a continuous and scalable process. In this manuscript, progress on preparation of special powders using HF thermal plasma in our team was introduced. Powders with large size were fed into plasma flame and vaporized to make them vaporation, and ultrafine powders were produced after fast quenching by physical vapor deposition (PVD). Spherical nanopowders of Si, Fe, Co, Ni could be prepared by PVD. Synthesized Si nanopowders display perfect spherical shape with smooth surface and good dispersity, which exhibit super electrochemical performance as anode for Li-ion batteries. Powders with irregular shape fed into plasma flame were melted to form spherical liquid drops and fast quenched to form spherical powders. W, Mo, Nb, Cr, Ni, Ti, V spherical powders could be prepared using HF thermal plasma. Hydrogen plasma with reactive radicals could help to enhance the hydrogen reductive reaction, which could make precursors to be reduced transiently to get metal nanopowders by chemical vapor deposition (CVD). W, Ni and Cu spherical nanopowders could be prepared using CVD. Synthesized W nanopowders with well defined spherical particles exhibit high sintering activity and strengthen the mechanical properties of obtained compacts. Oxygen plasma with reactive radicals can help to tune the growth of oxides in the plasma, and oxides with various morphologies can be produced using oxygen plasma. Al2O3 spherical nanopowders can be prepared and their sintering behavior shows that the aggregates are avoided and the grains are always uniform during sintering, owing to the employment of well dispersed spheres.
Fangli YUAN Huacheng JIN Guolin HOU Liuyang BAI Fei DING Baoqiang LI Yunfa CHEN
. Progress on preparation of special powders using HF thermal plasma[J]. The Chinese Journal of Process Engineering, 2018
, 18(6)
: 1138
-1144
.
DOI: 10.12034/j.issn.1009-606X.218240
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