Kyushu University Academic Staff Educational and Research Activities Database
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Manabu Tanaka Last modified date:2018.06.08

Assistant Professor / Product System Engineering
Department of Chemical Engineering
Faculty of Engineering

Graduate School
Undergraduate School
Other Organization

Academic Degree
Doctor of Engineering
Field of Specialization
Plasma Chemistry,Plasma diagnostics
Research Interests
  • Visualization of Arc Discharge Phenomena and Electrode Phenomena
    keyword : Thermal Plasma, Arc Phenomena, Fluctuation Phenomena, Electrode Phenomena, Visualization
  • Development of Nanomaterial Fabrication Processes by Thermal Plasmas
    keyword : Thermal Plasma, Atmospheric Pressure Plasma, Nanomaterials, Plasma Chemistry
Academic Activities
1. Manabu Tanaka, Takayuki Watanabe, Vaporization mechanism from Sn-Ag mixture by Ar-H2 Arc for nanoparticle preparation, Thin Solid Films,, 516, 19, 6645-6649, 2008.08, The purpose of this paper was to describe the synthesis of Sn-Ag nanoparticles by an arc plasma method. Sn-Ag nanoparticles have been successfully prepared by DC arc plasma with hydrogen addition. The prepared nanoparticles were characterized by X-Ray diffraction, transmission electron microscopy and inductively coupled plasma-atomic emission spectrometry. The obtained results indicated that the nanoparticles have high-purity and spherical shape. The average diameter of the nanoaprticles with 100%-Ar arc was 19.8 nm and that with 50%-H2 arc was 56.5 nm. Another purpose of this work is to investigate the vaporization behavior from molten Sn-Ag mixture with Ar and Ar-H2 arc. We confirmed the vaporization enhancement of Sn from Sn-Ag mixture by hydrogen in arc plasma..
2. Manabu Tanaka, Taro Hashizume, Koki Saga, Tsugio Matsuura, Takayuki Watanabe, Diode-rectified multiphase AC arc for the improvement of electrode erosion characteristics, Journal Physics D: Applied Physics,, 50, 46, 2017.10, An innovative multiphase AC arc (MPA) system was developed on the basis of a diode-rectification technique to improve electrode erosion characteristics. Conventionally, electrode erosion in AC arc is severer than that in DC arc. This originated from the fact that the required properties for the cathode and anode are different, although an AC electrode works as the cathode and the anode periodically. To solve this problem, a separation of AC electrodes into pairs of thoriated tungsten cathode and copper anode by diode-rectification was attempted. A diode-rectified multiphase AC arc (DRMPA) system was then successfully established, resulting in a drastic improvement of the erosion characteristics. The electrode erosion rate in the DRMPA was less than one-third of that in the conventional MPA without the diode rectification. In order to clarify its erosion mechanism, electrode phenomena during discharge were visualized by a high-speed camera system with appropriate band-pass filters. Fluctuation characteristics of the electrode temperature in the DRMPA were revealed..
1. Manabu Tanaka, Kohki Saga, Taro Hashizume,Tsugio Matsuura, Takayuki Watanabe, Improvement of Electrode Erosion Characteristics in Diode-Rectified Multiphase AC Arc, 23rd International Symposium on Plasma Chemistry, 2017.07, An innovative multiphase AC arc was drastically improved by diode-rectification technique. Conventionally, electrode erosion in AC arc originates from a lack of suitable electrode material because required properties for cathode and anode are different. To solve this problem, separation of AC electrodes into pairs of cathode and anode by diode-rectification was attempted. Diode-rectified MPA was then successfully established and erosion characteristics were drastically improved..
2. Tanaka Manabu, Yuji Nawata, Tomoyuki Imatsuji, Takayuki Watanabe, Dynamic Behavior of Metal Oxide Vapors in Multiphase AC Arc during Oxide Nanoparticle Fabrication Process, 26th Symposium of The Materials Research Society of Japan, 2016.12.
3. Manabu Tanaka, Taro Hashizume, Tomoyuki Imatsuji, Yushi Nawata, Takayuki Watanabe, High-Speed Visualization of Evaporation Phenomena from Tungsten Based Electrode in Multi-Phase AC Arc, 9th International Conference on Reactive Plasmas, 2015.10.
4. Taro Hashizume, Manabu Tanaka, Takayuki Watanabe, Droplet Ejection Mechanism from Tungsten Electrode in Multi-Phase AC Arc by High-Speed Visualization, 22nd International Symposium on Plasma Chemistry, 2015.07.
5. Manabu Tanaka, Takayuki Watanabe, High-Speed Visualization of Electrode Phenomena in Thermal Plasma Processing, 5th International Conference on Microelectronics and Plasma Technology, 2014.07, A multi-phase AC arc has been developed to apply to innovative in-flight glass melting technology as a promising heat source because it possesses following advantages; the high energy efficiency, the large plasma volume, the low gas velocity, and so on. However, the understanding of multi-phase AC arc still remains to be improved for the practical use. In particular, electrode erosion is one of the most important issues to be solved. The purpose of this study is to investigate the electrode erosion mechanism of the multi-phase arc.
Multi-phase AC arc reactor mainly consisted of 12 electrodes, arc chamber, and AC power supply. The electrodes were made of tungsten (98 wt%) and thoria (2 wt%) with diameter of 6 mm. Argon shield gas was injected around the electrode to prevent them from the oxidation because the melting point of tungsten oxide is lower than that of metal tungsten. As the multi-phase arc discharge was generated under the atmospheric air except of the above mentioned argon, the plasma source gas was mainly air. The argon gas flow rate was changed to investigate the shield gas effect on the electrode erosion.
Combination of the high-speed camera and the band-pass filters system enables to measure the electrode temperature even during arc discharge, and to observe dynamic behavior of the vapors in the arc. In the present work, two synchronized high-speed cameras were applied to investigate the erosion mechanism. One of the systems was used to measure the electrode temperature, while another one was synchronized to observe the vapors in the arc.
The strong tungsten emission separated from the other emissions was successfully observed at the anodic period in the case of lower argon gas flow rate. Moreover, the synchronized temperature measurements revealed that the electrode tip temperature increased with decreasing the argon gas flow rate. This is because the discharge point was stabilized due to the constriction of arc in anodic period at the lower flow rate of shield gas. The droplet ejection from the molten electrode surface was also observed in the case of lower shield gas flow rate. The droplet ejection was contributed to the high electrode erosion of the multi-phase arc.
The high-speed visualization by the synchronized system of high-speed video cameras with appropriate band-pass filters is important to understand electrode phenomena during thermal plasma processing..
6. Manabu Tanaka, Tomoki Ikeba, Yaping Liu, Sooseok Choi, Takayuki Watanabe, Investigation on Electrode Erosion Mechanism of Multi-Phase AC Arc by High-Speed Camera Observation, 21st International Symposium on Plasma Chemistry, 2013.08.
7. Manabu Tanaka, Takayuki Watanabe, Metal Hydride Formation from Molten Metal Surface by Ar-H2 Arc, 10th Asia-Pacific Conference on Plasma Science and Technology, 2010.07.
Membership in Academic Society
  • The Society of Chemical Engineering, Japan
  • The Japan Society of Applied Physics
  • The Japan Society of Plasma Science and Nuclear Fusion Research
  • Visualization of electrode erosion phenomena in multiphase AC arc by high-speed camera with band-pass filter system
  • M. Tanaka et al. have been awarded a Poster Prize for their poster contribution entitled "Fluctuation ohenomena in multiphase AC arc for nanoparticles fabrication".