The significant role of ion beam flux during nitriding 304 austenitic stainless steel has been investigated by using a radio frequency inductively-coupled plasma reactor into which a sample with negative bias voltage ...The significant role of ion beam flux during nitriding 304 austenitic stainless steel has been investigated by using a radio frequency inductively-coupled plasma reactor into which a sample with negative bias voltage was inserted. A milliammeter is used to detect tile current of ions which collide with the sample and optical emission spectroscopy is used to discern the reactive species included in the nitrogen plasma. The nitriding efficiency is indicated by X-ray diffraction and the microhardness test. The reported data reveal that the ion beam flux density as well as the deposition pressure, bias voltage and time can strongly affect the nitriding of stainless steel via tile expanded multiphase microstructure inside the nitrided layer. The increase in the density of ion flux results in an ascent in the intensity of the expanded peak and a simultaneous decline in the intensity of the 3＇ austenite peak. The evolution trend of ion beam flux density is described as a function of tile operating pressure and the bias voltage. The maxinmm ion flux density has been achieved at 10 Pa pressure and 500 V bias voltage. A reasonable nitriding region has been, consequently, suggested after comparing this work with previously reported results.展开更多
Plasmas containing ion beams have various applications both in plasma technology and in fundamental research. The ion beam energy and flux are the two factors characterizing the beam properties. Previous studies have ...Plasmas containing ion beams have various applications both in plasma technology and in fundamental research. The ion beam energy and flux are the two factors characterizing the beam properties. Previous studies have not achieved the independent adjustment of these two parameters. In this paper, an ion-beam-background-plasma system was produced with hotcathode discharge in a double plasma device separated by two adjacent grids, with which the beam energy and flux ratio （the ratio between the beam flux and total ion flux） can be controlled independently. It is shown that the discharge voltage （i.e., voltage across the hot-cathode and anode） and the voltage drop between the two separation grids can be used to effectively control the beam energy while the flux ratio is not affected by these voltages. The flux ratio depends sensitively on hot-filaments heating current whose influence on the beam energy is relatively weak, and thus enabling approximate control of the flux ratio展开更多
A high-flux linear plasma device in Sichuan University plasma-surface interaction（SCU-PSI）based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the ...A high-flux linear plasma device in Sichuan University plasma-surface interaction（SCU-PSI）based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the plasma-facing components in fusion reactors.In this paper,the helium plasma has been characterized by a double-pin Langmuir probe.The results show that the stable helium plasma beam with a diameter of 26 mm was constrained very well at a magnetic field strength of 0.3 T.The core density and ion flux of helium plasma have a strong dependence on the applied current,magnetic field strength and gas flow rate.It could reach an electron density of1.2×10^19m^-3and helium ion flux of 3.2×10^22m^-2s^-1,with a gas flow rate of 4 standard liter per minute,magnetic field strength of 0.2 T and input power of 11 k W.With the addition of-80 Vapplied to the target to increase the helium ion energy and the exposure time of 2 h,the flat top temperature reached about 530°C.The different sizes of nanostructured fuzz on irradiated tungsten and molybdenum samples surfaces under the bombardment of helium ions were observed by scanning electron microscopy.These results measured in the SCU-PSI linear device provide a reference for International Thermonuclear Experimental Reactor related PSI research.展开更多
基金supported by Shenyang Science and Technology Plan of China(No.F12028200)
文摘The significant role of ion beam flux during nitriding 304 austenitic stainless steel has been investigated by using a radio frequency inductively-coupled plasma reactor into which a sample with negative bias voltage was inserted. A milliammeter is used to detect tile current of ions which collide with the sample and optical emission spectroscopy is used to discern the reactive species included in the nitrogen plasma. The nitriding efficiency is indicated by X-ray diffraction and the microhardness test. The reported data reveal that the ion beam flux density as well as the deposition pressure, bias voltage and time can strongly affect the nitriding of stainless steel via tile expanded multiphase microstructure inside the nitrided layer. The increase in the density of ion flux results in an ascent in the intensity of the expanded peak and a simultaneous decline in the intensity of the 3＇ austenite peak. The evolution trend of ion beam flux density is described as a function of tile operating pressure and the bias voltage. The maxinmm ion flux density has been achieved at 10 Pa pressure and 500 V bias voltage. A reasonable nitriding region has been, consequently, suggested after comparing this work with previously reported results.
基金supported by National Natural Science Foundation of China(Nos.11575183,11175177)
文摘Plasmas containing ion beams have various applications both in plasma technology and in fundamental research. The ion beam energy and flux are the two factors characterizing the beam properties. Previous studies have not achieved the independent adjustment of these two parameters. In this paper, an ion-beam-background-plasma system was produced with hotcathode discharge in a double plasma device separated by two adjacent grids, with which the beam energy and flux ratio （the ratio between the beam flux and total ion flux） can be controlled independently. It is shown that the discharge voltage （i.e., voltage across the hot-cathode and anode） and the voltage drop between the two separation grids can be used to effectively control the beam energy while the flux ratio is not affected by these voltages. The flux ratio depends sensitively on hot-filaments heating current whose influence on the beam energy is relatively weak, and thus enabling approximate control of the flux ratio
基金supported by International Thermonuclear Experimental Reactor(ITER) program special(Grant No.2013GB114003)National Natural Science Foundation of China(project approval Nos.11275135,11475122)
文摘A high-flux linear plasma device in Sichuan University plasma-surface interaction（SCU-PSI）based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the plasma-facing components in fusion reactors.In this paper,the helium plasma has been characterized by a double-pin Langmuir probe.The results show that the stable helium plasma beam with a diameter of 26 mm was constrained very well at a magnetic field strength of 0.3 T.The core density and ion flux of helium plasma have a strong dependence on the applied current,magnetic field strength and gas flow rate.It could reach an electron density of1.2×10^19m^-3and helium ion flux of 3.2×10^22m^-2s^-1,with a gas flow rate of 4 standard liter per minute,magnetic field strength of 0.2 T and input power of 11 k W.With the addition of-80 Vapplied to the target to increase the helium ion energy and the exposure time of 2 h,the flat top temperature reached about 530°C.The different sizes of nanostructured fuzz on irradiated tungsten and molybdenum samples surfaces under the bombardment of helium ions were observed by scanning electron microscopy.These results measured in the SCU-PSI linear device provide a reference for International Thermonuclear Experimental Reactor related PSI research.
