Spherical tungsten and titanium powders were prepared by radio frequency inductively coupled plasma torch with irregular shaped tungsten and titanium hydride （TiH2） powders, respectively. The effect of the feed rate...Spherical tungsten and titanium powders were prepared by radio frequency inductively coupled plasma torch with irregular shaped tungsten and titanium hydride （TiH2） powders, respectively. The effect of the feed rate on spheroidization efficiency was investigated. The phase composition, oxygen content, morphology, and particle size distribution of the powders before and after spheroidization were characterized by X-ray diffraction （XRD）, nitrogen/oxygen analyzer, scanning electron microscopy （SEM）, and laser micron sizer （LMS）. The results show that both kinds of plasma-processed powders have good dispersity, smooth surface, and single phase. A maximum of 100 % of spheroidization efficiency can be achieved at a lower feed rate. The spherical titanium powder obtained by the plasma treatment consists of particles with mean diameter of 33.34 gin, while the mean diameter of ori- ginal Till2 powder is 136.56 μm. The apparent density and flowability of the spherical tungsten powder are 6.3 g.cm-3 and 0.16 s.g-1, respectively. The apparent density and flowability of the spherical titanium powder are 2.8 g.cm-3 and 0.52 s.g-1, respectively. With the increase of the feed rate, the sphemidization efficiency of raw powders drops gradually.展开更多
The production of high quality single-walled carbon nanotubes(SWCNTs)on a bulk scale has been an issue of considerable interest.Recently,it has been demonstrated that high quality SWCNTs can be continuously synthesize...The production of high quality single-walled carbon nanotubes(SWCNTs)on a bulk scale has been an issue of considerable interest.Recently,it has been demonstrated that high quality SWCNTs can be continuously synthesized on large scale by using induction thermal plasma technology.In this process,the high energy density of the thermal plasma is employed to generate dense vapor-phase precursors for the synthesis of SWCNTs.With the current reactor system,a carbon soot product which contains approximately 40 wt%of SWCNTs can be continuously synthesized at the high production rate of~100 g/h.In this article,our recent research efforts to achieve major advances in this technology are presented.Firstly,the processing parameters involved are examined systematically in order to evaluate their individual inuences on the SWCNT synthesis.Based on these results,the appropriate operating conditions of the induction thermal plasma process for an effective synthesis of SWCNTs are discussed.A characterization study has also been performed on the SWCNTs produced under the optimum processing conditions.Finally,a mathematical model of the process currently under development is described.The model will help us to better understand the synthesis of SWCNTs in the induction plasma process.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51274039)the Research Fund for the Doctoral Program of Higher Education of China(No.20120006110007)
文摘Spherical tungsten and titanium powders were prepared by radio frequency inductively coupled plasma torch with irregular shaped tungsten and titanium hydride （TiH2） powders, respectively. The effect of the feed rate on spheroidization efficiency was investigated. The phase composition, oxygen content, morphology, and particle size distribution of the powders before and after spheroidization were characterized by X-ray diffraction （XRD）, nitrogen/oxygen analyzer, scanning electron microscopy （SEM）, and laser micron sizer （LMS）. The results show that both kinds of plasma-processed powders have good dispersity, smooth surface, and single phase. A maximum of 100 % of spheroidization efficiency can be achieved at a lower feed rate. The spherical titanium powder obtained by the plasma treatment consists of particles with mean diameter of 33.34 gin, while the mean diameter of ori- ginal Till2 powder is 136.56 μm. The apparent density and flowability of the spherical tungsten powder are 6.3 g.cm-3 and 0.16 s.g-1, respectively. The apparent density and flowability of the spherical titanium powder are 2.8 g.cm-3 and 0.52 s.g-1, respectively. With the increase of the feed rate, the sphemidization efficiency of raw powders drops gradually.
基金This work was supported by the Natural Science and Engineering Research Council(NSERC)of Canada.
文摘The production of high quality single-walled carbon nanotubes(SWCNTs)on a bulk scale has been an issue of considerable interest.Recently,it has been demonstrated that high quality SWCNTs can be continuously synthesized on large scale by using induction thermal plasma technology.In this process,the high energy density of the thermal plasma is employed to generate dense vapor-phase precursors for the synthesis of SWCNTs.With the current reactor system,a carbon soot product which contains approximately 40 wt%of SWCNTs can be continuously synthesized at the high production rate of~100 g/h.In this article,our recent research efforts to achieve major advances in this technology are presented.Firstly,the processing parameters involved are examined systematically in order to evaluate their individual inuences on the SWCNT synthesis.Based on these results,the appropriate operating conditions of the induction thermal plasma process for an effective synthesis of SWCNTs are discussed.A characterization study has also been performed on the SWCNTs produced under the optimum processing conditions.Finally,a mathematical model of the process currently under development is described.The model will help us to better understand the synthesis of SWCNTs in the induction plasma process.
基金National Natural Science Foundation of China(51274039)State Key Laboratory for Advanced Metals and Materials(2010Z-09)Research Fund for 2012 Doctoral Program of Higher Education(20120006110007)
