The stainless steel （SS） first mirror pre-exposed in the deposition-dominated envi- ronment of the HT-7 tokamak was cleaned in the newly built radio frequency （RF） magnetron sputtering plasma device. The depositio...The stainless steel （SS） first mirror pre-exposed in the deposition-dominated envi- ronment of the HT-7 tokamak was cleaned in the newly built radio frequency （RF） magnetron sputtering plasma device. The deposition layer on the FM surface formed during the exposure was successfully removed by argon plasma with a RF power of about 80 W and a gas pressure of 0.087 Pa for 30 min. The total reflectivity of the mirrors was recovered up to 90% in the wavelength range of 300-800 nm, while the diffuse reflectivity showed a little increase, which was attributed to the increase of surface roughness in sputtering, and residual contaminants. The FMs made from single crystal materials could help to achieve a desired recovery of specular reflectivity in the future.展开更多
He-charged oxide dispersion strengthened （ODS） FeCrNi fills were prepared by a radiofrequency （RF） plasma magnetron sputtering method in a He and Ar mixed atmosphere at 150 °C.As a comparison,He-charged FeCrN...He-charged oxide dispersion strengthened （ODS） FeCrNi fills were prepared by a radiofrequency （RF） plasma magnetron sputtering method in a He and Ar mixed atmosphere at 150 °C.As a comparison,He-charged FeCrNi films were also fabricated at the same conditions through direct current （DC） plasma magnetron sputtering.The doping of He atoms and Y2O3 in the FeCrNi fills was realized by the high backscattered rate of He ions and Y2O3/FeCrNi composite target sputtering method,respectively.Inductive coupled plasma （ICP） and x-ray photoelectron spectroscopy （XPS） analysis confirmed the existence of Y2O3 in FeCrNi fills,and Y2O3 content hardly changed with sputtering He/Ar ratio.Cross-sectional scanning electron microscopy （SEM） shows that the FeCrNi films were composed of dense colunnarnanocrystallines and the thickness of the films was obviously dependent on He/Ar ratio.Nanoindentation measurements revealed that the FeCrNi films fabricated through DC/RF plasma magnetron sputtering methods exhibited similar hardness values at each He/Ar ratio,while the dispersion of Y2O3 apparently increased the hardness of the fills.Elastic recoil detection （ERD） showed that DC/RF magnetron sputtered FeCrNi films contained similar He amounts （～17 at.%）.Compared with the minimal change of He level with depth in DC-sputtered films,the He amount decreases gradually in depth in the RF-sputtered fills.The Y2O3-doped FeCrNi films were shown to exhibit much smaller amounts of He owing to the lower backscattering possibility of Y2O3 and the inhibition effect of nano-sized Y2O3 particles on the He element.展开更多
Two kinds nitride modified layers were obtained on Ti-13Nb-13 Zr surface to improve the wear property via magnetron sputtering and plasma nitriding techniques, respectively. The structures of the modified layer and th...Two kinds nitride modified layers were obtained on Ti-13Nb-13 Zr surface to improve the wear property via magnetron sputtering and plasma nitriding techniques, respectively. The structures of the modified layer and the worn surface after sliding test were characterized using X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The friction and wear behavior of the modified layer against alumina ball was investigated in the absence of lubricant under different loads（1 N and 2 N）. The X-ray diffraction analysis reveals that nitride layer is mainly composed of TiN and Ti2N, while coating film consists of Ti N phase. Friction and wear test indicates that both modified layers can improve the wear resistance compared to untreated Ti-13Nb-13 Zr. Ti N thin film produces very hard surface, but may be easy to cause coating fracture and delamination under high normal load. However, nitride layer exhibits better wear performance. This is attributed to hard compound layer maintained its integrity with the hardened nitrogen diffusion zone during friction and wear process.展开更多
Low-Z materials, such as carbon-based materials and Be, are major plasma-facing material (PFM) for current, even in future fusion devices. In this paper, a new type of multielement-doped carbon-based materials develop...Low-Z materials, such as carbon-based materials and Be, are major plasma-facing material (PFM) for current, even in future fusion devices. In this paper, a new type of multielement-doped carbon-based materials developed are presented along with experimental re-sults of their properties. The results indicate a decrease in chemical sputtering yield by one order of magnitude, a decrease in both thermal shock resistance and radiation-enhanced sublimation, an evidently lower temperature desorption spectrum, and combined properties of exposing to plasma.展开更多
Plasma sputtering deposition techniques are good candidates for the fabrication of electrodes used for direct methanol fuel cells （DMFCs）. A house-made plasma sputtering system was used to deposit platinum of 0.1 mg...Plasma sputtering deposition techniques are good candidates for the fabrication of electrodes used for direct methanol fuel cells （DMFCs）. A house-made plasma sputtering system was used to deposit platinum of 0.1 mg/cm^2 onto un-catalyzed gas diffusion layers （GDLs） to form a Pt catalyzed cathode at different radio frequency （RF） powers and sputtering-gas pressures. The sputtered cathodes were assembled in custom-made membrane electrode assemblies （MEAs） with a commercial anode and tested for the electrical performance of the single cell. A custommade MEA with a sputtering prepared cathode was compared with that of a reference membrane electrode assembly made of commercial JM （Johnson Mattey） catalysts （Pt loading per electrode of 0.5 mg/cm^2） under passive methanol supply, ambient temperature and air-breathing conditions. The results showed that the cathode prepared at an input power of 110 W and sputtering-gas pressure of 5.3 Pa exhibited the best cell performance and highest Pt utilization efficiency, which was due to the miniaturization of the Pt particles and formation of the porous catalyst layer. Although the single cell performance of the commercial cathode was better than all the sputtering fabricated cathodes, the Pt utilization efficiency of all the sputtered cathodes was higher than that of the commercial cathode.展开更多
Anodes used for direct methanol fuel cells （DMFCs） were fabricated by magnetron sputtering process. A house-made plasma sputtering system was used to deposit Pt and PtRu onto un-catalyzed gas diffusion layers （GDLs...Anodes used for direct methanol fuel cells （DMFCs） were fabricated by magnetron sputtering process. A house-made plasma sputtering system was used to deposit Pt and PtRu onto un-catalyzed gas diffusion layers （GDLs） at different radio frequency （RF） powers and sputtering- gas pressures. The thin film catalyst layers were characterized by X-ray diffraction, energy dis- persive X-ray analysis, and X-ray photoelectron spectroscopy. The sputtered anodes were assem- bled in custom-made membrane electrode assemblies （MEAs） with a commercial cathode and the electrical performance of the single cell were tested under passive methanol supply, ambient tern- perature and air-breathing conditions. The electrochemical performance of the anodes prepared with PtRu alloy was compared with a reference anode sputtered with Pt only. X-ray diffraction and X-ray photoelectron spectroscopy revealed that platinum and ruthenium existed as a form of alloy. The cell polarization measurements showed that all the PtRu alloy catalysts had better electrochemical performance than the Ptl catalyst, and the Pto.n3Ruo.57 catalyst achieved the best performance.展开更多
In this study, plasma nitriding was used to fabricate a hard protective layer on AISI P20 steel, at three process temperatures（450℃, 500℃, and 550℃） and over a range of time periods（2.5, 5, 7.5, and 10 h）, and ...In this study, plasma nitriding was used to fabricate a hard protective layer on AISI P20 steel, at three process temperatures（450℃, 500℃, and 550℃） and over a range of time periods（2.5, 5, 7.5, and 10 h）, and at a fixed gas N2：H2 ratio of 75vol%：25vol%. The morphology of samples was studied using optical microscopy and scanning electron microscopy, and the formed phase of each sample was determined by X-ray diffraction. The elemental depth profile was measured by energy dispersive X-ray spectroscopy, wavelength dispersive spectroscopy, and glow dispersive spectroscopy. The hardness profile of the samples was identified, and the microhardness profile from the surface to the sample center was recorded. The results show that ε-nitride is the dominant species after carrying out plasma nitriding in all strategies and that the plasma nitriding process improves the hardness up to more than three times. It is found that as the time and temperature of the process increase, the hardness and hardness depth of the diffusion zone considerably increase. Furthermore, artificial neural networks were used to predict the effects of operational parameters on the mechanical properties of plastic mold steel. The plasma temperature, running time of imposition, and target distance to the sample surface were all used as network inputs; Vickers hardness measurements were given as the output of the model. The model accurately reproduced the experimental outcomes under different operational conditions; therefore, it can be used in the effective simulation of the plasma nitriding process in AISI P20 steel.展开更多
In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is desc...In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is described. Furthermore,the contact stress evolution processes of layered surface with and without transfer layer during wear are given for understanding the contact mechanisms. Finally,a three-dimension (3D) local yield map of layered surface is introduced,which is useful to predict the possible contact mechanisms.展开更多
Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma s...Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.展开更多
This paper reports that amorphous silicon nitride （a-SiNx） overcoats were deposited at room temperature by microwave ECR plasma enhanced unbalanced magnetron sputtering. The 2 nm a-SiNs overcoat has better anti-corr...This paper reports that amorphous silicon nitride （a-SiNx） overcoats were deposited at room temperature by microwave ECR plasma enhanced unbalanced magnetron sputtering. The 2 nm a-SiNs overcoat has better anti-corrosion properties than that of reference a-CNx overcoats （2 4.5 nm）. The superior anti-corrosion performance is attributed to its stoichiometric bond structure, where 94.8% Si atoms form Si-N asymmetric stretching vibration bonds. The N/Si ratio is 1.33 as in the stoichiometry of Si3N4 and corresponds to the highest hardness of 25.0 GPa. The surface is atomically smooth with RMS 〈 0.2 nm. The ultra-thin a-SiNx overcoats are promising for hard disks and read/write heads protective coatings.展开更多
Herein we report the successful preparation of silver(Ag)-decorated vertically oriented graphene sheets(Ag/VGs)via helicon wave plasma chemical vapor deposition(HWP-CVD)and radiofrequency plasma magnetron sputtering(R...Herein we report the successful preparation of silver(Ag)-decorated vertically oriented graphene sheets(Ag/VGs)via helicon wave plasma chemical vapor deposition(HWP-CVD)and radiofrequency plasma magnetron sputtering(RF-PMS).VGs were synthesized in a mixture of argon and methane(Ar/CH_(4))by HWP-CVD and then the Ag nanoparticles on the prepared VGs were modified using the RF-PMS system for different sputtering times and RF power levels.The morphology and structure of the Ag nanoparticles were characterized by scanning electron microscopy and the results revealed that Ag nanoparticles were evenly dispersed on the mesoporous wall of the VGs.X-ray diffraction results showed that the diameter of the Ag particles increased with the increase in Ag loading,and the average size was between 10.49 nm and 25.9 nm,consistent with the transmission electron microscopy results.Ag/VGs were investigated as effective electrocatalysts for use in an alkaline aqueous system.Due to the uniquely ordered and interconnected wall structure of VGs,the area of active sites increased with the Ag loading,giving the Ag/VGs a good performance in the oxygen evolution reaction.The double-layer capacitance(C_(dl))of the Ag/VGs under different Ag loadings were studied,and the results showed that the highest Ag content gave the best C_(dl)(1.04 mF cm^(-2)).Our results show that Ag/VGs are likely to be credible electrocatalytic materials.展开更多
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2013GB105003)National Natural Science Foundation of China(No.11175205)
文摘The stainless steel （SS） first mirror pre-exposed in the deposition-dominated envi- ronment of the HT-7 tokamak was cleaned in the newly built radio frequency （RF） magnetron sputtering plasma device. The deposition layer on the FM surface formed during the exposure was successfully removed by argon plasma with a RF power of about 80 W and a gas pressure of 0.087 Pa for 30 min. The total reflectivity of the mirrors was recovered up to 90% in the wavelength range of 300-800 nm, while the diffuse reflectivity showed a little increase, which was attributed to the increase of surface roughness in sputtering, and residual contaminants. The FMs made from single crystal materials could help to achieve a desired recovery of specular reflectivity in the future.
基金financially supported by National Natural Science Foundation of China(No.11374299)
文摘He-charged oxide dispersion strengthened （ODS） FeCrNi fills were prepared by a radiofrequency （RF） plasma magnetron sputtering method in a He and Ar mixed atmosphere at 150 °C.As a comparison,He-charged FeCrNi films were also fabricated at the same conditions through direct current （DC） plasma magnetron sputtering.The doping of He atoms and Y2O3 in the FeCrNi fills was realized by the high backscattered rate of He ions and Y2O3/FeCrNi composite target sputtering method,respectively.Inductive coupled plasma （ICP） and x-ray photoelectron spectroscopy （XPS） analysis confirmed the existence of Y2O3 in FeCrNi fills,and Y2O3 content hardly changed with sputtering He/Ar ratio.Cross-sectional scanning electron microscopy （SEM） shows that the FeCrNi films were composed of dense colunnarnanocrystallines and the thickness of the films was obviously dependent on He/Ar ratio.Nanoindentation measurements revealed that the FeCrNi films fabricated through DC/RF plasma magnetron sputtering methods exhibited similar hardness values at each He/Ar ratio,while the dispersion of Y2O3 apparently increased the hardness of the fills.Elastic recoil detection （ERD） showed that DC/RF magnetron sputtered FeCrNi films contained similar He amounts （～17 at.%）.Compared with the minimal change of He level with depth in DC-sputtered films,the He amount decreases gradually in depth in the RF-sputtered fills.The Y2O3-doped FeCrNi films were shown to exhibit much smaller amounts of He owing to the lower backscattering possibility of Y2O3 and the inhibition effect of nano-sized Y2O3 particles on the He element.
基金Funded by the National Natural Science Foundation of China(Nos.51671140 and 51474154)the Shanxi Province Programs for Graduate Education Reform(2015JG42)
文摘Two kinds nitride modified layers were obtained on Ti-13Nb-13 Zr surface to improve the wear property via magnetron sputtering and plasma nitriding techniques, respectively. The structures of the modified layer and the worn surface after sliding test were characterized using X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The friction and wear behavior of the modified layer against alumina ball was investigated in the absence of lubricant under different loads（1 N and 2 N）. The X-ray diffraction analysis reveals that nitride layer is mainly composed of TiN and Ti2N, while coating film consists of Ti N phase. Friction and wear test indicates that both modified layers can improve the wear resistance compared to untreated Ti-13Nb-13 Zr. Ti N thin film produces very hard surface, but may be easy to cause coating fracture and delamination under high normal load. However, nitride layer exhibits better wear performance. This is attributed to hard compound layer maintained its integrity with the hardened nitrogen diffusion zone during friction and wear process.
基金The work was supported by the National Nature Science Foundation of China No.19789503.
文摘Low-Z materials, such as carbon-based materials and Be, are major plasma-facing material (PFM) for current, even in future fusion devices. In this paper, a new type of multielement-doped carbon-based materials developed are presented along with experimental re-sults of their properties. The results indicate a decrease in chemical sputtering yield by one order of magnitude, a decrease in both thermal shock resistance and radiation-enhanced sublimation, an evidently lower temperature desorption spectrum, and combined properties of exposing to plasma.
基金supported by National Natural Science Foundation of China (No. 10975162)the Principal Foundation of Institute of Plasma PhysicsChinese Academy of Sciences (No. 095GZ1156Y)
文摘Plasma sputtering deposition techniques are good candidates for the fabrication of electrodes used for direct methanol fuel cells （DMFCs）. A house-made plasma sputtering system was used to deposit platinum of 0.1 mg/cm^2 onto un-catalyzed gas diffusion layers （GDLs） to form a Pt catalyzed cathode at different radio frequency （RF） powers and sputtering-gas pressures. The sputtered cathodes were assembled in custom-made membrane electrode assemblies （MEAs） with a commercial anode and tested for the electrical performance of the single cell. A custommade MEA with a sputtering prepared cathode was compared with that of a reference membrane electrode assembly made of commercial JM （Johnson Mattey） catalysts （Pt loading per electrode of 0.5 mg/cm^2） under passive methanol supply, ambient temperature and air-breathing conditions. The results showed that the cathode prepared at an input power of 110 W and sputtering-gas pressure of 5.3 Pa exhibited the best cell performance and highest Pt utilization efficiency, which was due to the miniaturization of the Pt particles and formation of the porous catalyst layer. Although the single cell performance of the commercial cathode was better than all the sputtering fabricated cathodes, the Pt utilization efficiency of all the sputtered cathodes was higher than that of the commercial cathode.
基金supported by National Natural Science Foundation of China (No.10975162)the Principal Foundation of Institute of Plasma Physics, Chinese Academy of Sciences (No.095GZ1156Y)
文摘Anodes used for direct methanol fuel cells （DMFCs） were fabricated by magnetron sputtering process. A house-made plasma sputtering system was used to deposit Pt and PtRu onto un-catalyzed gas diffusion layers （GDLs） at different radio frequency （RF） powers and sputtering- gas pressures. The thin film catalyst layers were characterized by X-ray diffraction, energy dis- persive X-ray analysis, and X-ray photoelectron spectroscopy. The sputtered anodes were assem- bled in custom-made membrane electrode assemblies （MEAs） with a commercial cathode and the electrical performance of the single cell were tested under passive methanol supply, ambient tern- perature and air-breathing conditions. The electrochemical performance of the anodes prepared with PtRu alloy was compared with a reference anode sputtered with Pt only. X-ray diffraction and X-ray photoelectron spectroscopy revealed that platinum and ruthenium existed as a form of alloy. The cell polarization measurements showed that all the PtRu alloy catalysts had better electrochemical performance than the Ptl catalyst, and the Pto.n3Ruo.57 catalyst achieved the best performance.
文摘In this study, plasma nitriding was used to fabricate a hard protective layer on AISI P20 steel, at three process temperatures（450℃, 500℃, and 550℃） and over a range of time periods（2.5, 5, 7.5, and 10 h）, and at a fixed gas N2：H2 ratio of 75vol%：25vol%. The morphology of samples was studied using optical microscopy and scanning electron microscopy, and the formed phase of each sample was determined by X-ray diffraction. The elemental depth profile was measured by energy dispersive X-ray spectroscopy, wavelength dispersive spectroscopy, and glow dispersive spectroscopy. The hardness profile of the samples was identified, and the microhardness profile from the surface to the sample center was recorded. The results show that ε-nitride is the dominant species after carrying out plasma nitriding in all strategies and that the plasma nitriding process improves the hardness up to more than three times. It is found that as the time and temperature of the process increase, the hardness and hardness depth of the diffusion zone considerably increase. Furthermore, artificial neural networks were used to predict the effects of operational parameters on the mechanical properties of plastic mold steel. The plasma temperature, running time of imposition, and target distance to the sample surface were all used as network inputs; Vickers hardness measurements were given as the output of the model. The model accurately reproduced the experimental outcomes under different operational conditions; therefore, it can be used in the effective simulation of the plasma nitriding process in AISI P20 steel.
基金National Natural Science Foundation of China(No.90923027No.51175405)
文摘In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is described. Furthermore,the contact stress evolution processes of layered surface with and without transfer layer during wear are given for understanding the contact mechanisms. Finally,a three-dimension (3D) local yield map of layered surface is introduced,which is useful to predict the possible contact mechanisms.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 50842028 and 50972012)the National Basic Research Program of China (Grant No 2007CB613301)
文摘Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.
基金Project supported by the Major Program of the National Natural Science Foundation of China (Grant No 50390060)the National Natural Science Foundation of China (Grant Nos 60576022 and 50572012)
文摘This paper reports that amorphous silicon nitride （a-SiNx） overcoats were deposited at room temperature by microwave ECR plasma enhanced unbalanced magnetron sputtering. The 2 nm a-SiNs overcoat has better anti-corrosion properties than that of reference a-CNx overcoats （2 4.5 nm）. The superior anti-corrosion performance is attributed to its stoichiometric bond structure, where 94.8% Si atoms form Si-N asymmetric stretching vibration bonds. The N/Si ratio is 1.33 as in the stoichiometry of Si3N4 and corresponds to the highest hardness of 25.0 GPa. The surface is atomically smooth with RMS 〈 0.2 nm. The ultra-thin a-SiNx overcoats are promising for hard disks and read/write heads protective coatings.
基金supported by National Natural Science Foundation of China(No.11975163)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Herein we report the successful preparation of silver(Ag)-decorated vertically oriented graphene sheets(Ag/VGs)via helicon wave plasma chemical vapor deposition(HWP-CVD)and radiofrequency plasma magnetron sputtering(RF-PMS).VGs were synthesized in a mixture of argon and methane(Ar/CH_(4))by HWP-CVD and then the Ag nanoparticles on the prepared VGs were modified using the RF-PMS system for different sputtering times and RF power levels.The morphology and structure of the Ag nanoparticles were characterized by scanning electron microscopy and the results revealed that Ag nanoparticles were evenly dispersed on the mesoporous wall of the VGs.X-ray diffraction results showed that the diameter of the Ag particles increased with the increase in Ag loading,and the average size was between 10.49 nm and 25.9 nm,consistent with the transmission electron microscopy results.Ag/VGs were investigated as effective electrocatalysts for use in an alkaline aqueous system.Due to the uniquely ordered and interconnected wall structure of VGs,the area of active sites increased with the Ag loading,giving the Ag/VGs a good performance in the oxygen evolution reaction.The double-layer capacitance(C_(dl))of the Ag/VGs under different Ag loadings were studied,and the results showed that the highest Ag content gave the best C_(dl)(1.04 mF cm^(-2)).Our results show that Ag/VGs are likely to be credible electrocatalytic materials.
