Acrylic polyurethane paint on the surface of 2A12 Al alloy was cleaned utilizing an atmospheric pressure plasma jet in this work.The dynamic evolution of the paint removal process during plasma treatment with time was...Acrylic polyurethane paint on the surface of 2A12 Al alloy was cleaned utilizing an atmospheric pressure plasma jet in this work.The dynamic evolution of the paint removal process during plasma treatment with time was explored through analysis of morphology and chemical states.The results showed that although the thickness of paint could be reduced effectively with an increase in cleaning time,the removal rate of paint gradually decreased with time.During the initial cleaning process range,its original smooth morphology of paint turned rugged quickly and was almost unchanged with further plasma treatment.Element and chemical state analysis showed that the content of C in the paint layer decreased obviously after plasma treatment.In contrast,the O content increased remarkably.The cleaning mechanism could be mainly attributed to the reaction between active O-containing species in air plasma and organic components in the paint.After removal of superficial organic matter,residue inorganic metal oxide substances aggregated on the base.The exposed metal oxides on the one hand elevated the superficial O content,but on the other hand hindered further plasma penetration,resulting in a gradual decrease in cleaning rate with cleaning time.Therefore,physical wiping was proposed to be incorporated with the plasma method and effective removal of paint was realized.展开更多
Gas-driven permeation(GDP)and plasma-driven permeation(PDP)of hydrogen gas through Ga In Sn/Fe are systematically investigated in this work.The permeation parameters of hydrogen through Ga In Sn/Fe,including diffusivi...Gas-driven permeation(GDP)and plasma-driven permeation(PDP)of hydrogen gas through Ga In Sn/Fe are systematically investigated in this work.The permeation parameters of hydrogen through Ga In Sn/Fe,including diffusivity,Sieverts'constant,permeability,and surface recombination coefficient are obtained.The permeation flux of hydrogen through Ga In Sn/Fe shows great dependence on external conditions such as temperature,hydrogen pressure,and thickness of liquid Ga In Sn.Furthermore,the hydrogen permeation behavior through Ga In Sn/Fe is well consistent with the multilayer permeation theory.In PDP and GDP experiments,hydrogen through Ga In Sn/Fe satisfies the diffusion-limited regime.In addition,the permeation flux of PDP is greater than that of GDP.The increase of hydrogen plasma density hardly causes the hydrogen PDP flux to change within the test scope of this work,which is due to the dissolution saturation.These findings provide guidance for a comprehensive and systematic understanding of hydrogen isotope recycling,permeation,and retention in plasma-facing components under actual conditions.展开更多
Self-cleaning of tin contaminants was realized utilizing a self-driven hydrogen plasma.Cleaning rates of 0.7-6 nm min-1were achieved for removal of discontinuous tin particles at different powers.The analysis of topog...Self-cleaning of tin contaminants was realized utilizing a self-driven hydrogen plasma.Cleaning rates of 0.7-6 nm min-1were achieved for removal of discontinuous tin particles at different powers.The analysis of topography and cross-sectional morphology revealed that the removal of tin particles was achieved through top-down cleaning with hydrogen plasma,where the upper part of spherical tin particles was always more intensely cleaned under the synergistic effect of hydrogen atoms and ions due to the vertical incidence of ions to the substrate during the whole cleaning process.Redeposition of tin atoms caused by physical sputtering and its promotion of the chemical cleaning effect was observed for the first time.Reflectance recovery measurements during cleaning and surface analysis of the substrate after cleaning indicated that nondestructive cleaning with a reflectance loss of less than 1%can be achieved at a relatively low power of120 W.Plasma-induced substrate damage,such as holes and valleys,reduced the reflectance of the substrate when cleaning was performed at a high power greater than 120 W,so this method should only be considered for application under conditions without substrate exposure.This study provides a comprehensive understanding of the removal of discontinuous tin particles using the in situ self-driven plasma cleaning method,and also provides meaningful guidance for the extension of this method in other potential fields of application.展开更多
This study examined the effects of plasma irradiation on an unwetted liquid lithium-based capillary porous system(Li-CPS). The Li-CPS was irradiated with high-density Ar plasma using a linear plasma device at Sichuan ...This study examined the effects of plasma irradiation on an unwetted liquid lithium-based capillary porous system(Li-CPS). The Li-CPS was irradiated with high-density Ar plasma using a linear plasma device at Sichuan University for Plasma Surface Interaction. The high-speed camera, Langmuir probe, and multi-channel spectrometer were used to characterize the effects of plasma irradiation. Upon Ar plasma irradiation, liquid Li drops were formed on the surface of the unwetted Li-CPS. Immediately after this irradiation, the drops fractured and were ejected into the plasma within ~20 ms scale, which is not observed before to the best of our knowledge. Related results showed that the ejection behavior of Li could effectively cool electron temperature and reduce incident heat flux by ~30% and correspondingly matrix temperature ~150 ℃, revealing an enhanced vapor shielding effect. The involved internal mechanism and physical processes deserve further investigations.展开更多
Atmospheric pressure plasma jet(APPJ)was used to clean nitrogen-containing carbon films(C–N)fabricated by plasma-assisted chemical vapor deposition method employing the plasma surface interaction linear device at Sic...Atmospheric pressure plasma jet(APPJ)was used to clean nitrogen-containing carbon films(C–N)fabricated by plasma-assisted chemical vapor deposition method employing the plasma surface interaction linear device at Sichuan University(SCU-PSI).The properties of the contaminated films on the surface of pristine and He-plasma pre-irradiated tungsten matrix,such as morphology,crystalline structure,element composition and chemical structure were characterized by scanning electron microscopy,grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy.The experimental results revealed that the removal of C–N film with a thickness of tens of microns can be realized through APPJ cleaning regardless of the morphology of the substrates.Similar removal rates of 16.82 and 13.78μm min^(-1)were obtained for C–N films deposited on a smooth pristine W surface and rough fuzz-covered W surface,respectively.This is a remarkable improvement in comparison to the traditional cleaning method.However,slight surface oxidation was found after APPJ cleaning,but the degree of oxidation was acceptable with an oxidation depth increase of only 3.15 nm.Optical emission spectroscopy analysis and mass spectrometry analysis showed that C–N contamination was mainly removed through chemical reaction with reactive oxygen species during APPJ treatment using air as the working gas.These results make APPJ cleaning a potentially effective method for the rapid removal of C–N films from the wall surfaces of fusion devices.展开更多
The net erosion yield of CX-2002U carbon fiber composites under high-flux low-temperature hydrogen plasma is investigated using a linear plasma device.It is found that the net erosion yield decreases rapidly first,and...The net erosion yield of CX-2002U carbon fiber composites under high-flux low-temperature hydrogen plasma is investigated using a linear plasma device.It is found that the net erosion yield decreases rapidly first,and then tends to saturate with the increase of hydrogen–plasma flux.When the temperature of the sample eroded by hydrogen plasma is above 300°C,the hybridization of electrons outside the carbon atom would change.Then the carbon atoms combine with hydrogen atoms to form massive spherical nanoparticles of hydrocarbon compounds and deposit on the surface at the flux condition of 1.77×10^(22) m^(−2)·s^(−1).Under the irradiation of hydrogen plasma loaded with negative bias,the surface morphology of the matrix carbon is changed dramatically.Moreover,the energy dependence of mass loss does not increase in proportion to the increase of hydrogen–plasma energy,but reaches a peak around 20 V negative bias voltage.Based on the analysis of different samples,it can be concluded that the enhancement of energy could make a contribution to chemical erosion and enlarge the size of pores existing on the surface.展开更多
Steady high-flux helium(He)plasma with energy ranging from 50 eV to 90 eV is used to fabricate a fiber-form nanostructure called fuzz on a polycrystalline molybdenum(Mo)surface.Enhanced hydrogen(H)pulsed plasma in a w...Steady high-flux helium(He)plasma with energy ranging from 50 eV to 90 eV is used to fabricate a fiber-form nanostructure called fuzz on a polycrystalline molybdenum(Mo)surface.Enhanced hydrogen(H)pulsed plasma in a wide power density range of 12 MW/m^(2)-35 MW/m^(2)is subsequently used to bombard the fuzzy Mo,thereby simulating the damage of edge localized mode(ELM)to fuzz.The comparisons of surface morphologies,crystalline structures,and optical reflectivity between the original Mo and the Mo treated with various He^(+)energy and transient power densities are performed.With the increase of He ion energy,the Mo nano-fuzz evolved density is enlarged due to the decrease of filament diameter and optical reflectivity.The fuzz-enhanced He release should be the consequence of crystalline growth and the lattice shrinkage inside the Mo-irradiated layers(^(2)00 nm).The fuzz induced by lower energy experiences more severe melting damage and dust release under the condition of the identical transient H plasma-bombardment.The H and He are less likely to be trapped due to aggravated melting evidenced by the enhanced crystalline size and distinct lattice shrinkage.As the transient power density rises,the thermal effect is enhanced,thereby causing the fuzz melting loss to aggravate and finally to completely disappear when the power density exceeds 21 MW/m^(2).Irreversible grain expansion results in huge tensile stress,leading to the observable brittle cracking.The effects of transient thermal load and He ion energy play a crucial role in etching Mo fuzz during ELM transient events.展开更多
基金supported by National Natural Science Foundation of China(No.U21A20438)the Foundation of Key Laboratory of Radiation Physics and Technology of the Ministry of Education(No.2021SCURPT03)。
文摘Acrylic polyurethane paint on the surface of 2A12 Al alloy was cleaned utilizing an atmospheric pressure plasma jet in this work.The dynamic evolution of the paint removal process during plasma treatment with time was explored through analysis of morphology and chemical states.The results showed that although the thickness of paint could be reduced effectively with an increase in cleaning time,the removal rate of paint gradually decreased with time.During the initial cleaning process range,its original smooth morphology of paint turned rugged quickly and was almost unchanged with further plasma treatment.Element and chemical state analysis showed that the content of C in the paint layer decreased obviously after plasma treatment.In contrast,the O content increased remarkably.The cleaning mechanism could be mainly attributed to the reaction between active O-containing species in air plasma and organic components in the paint.After removal of superficial organic matter,residue inorganic metal oxide substances aggregated on the base.The exposed metal oxides on the one hand elevated the superficial O content,but on the other hand hindered further plasma penetration,resulting in a gradual decrease in cleaning rate with cleaning time.Therefore,physical wiping was proposed to be incorporated with the plasma method and effective removal of paint was realized.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11905151 and 11875198)the National Key Research and Development Program of China(Grant No.2022YFE03130000)。
文摘Gas-driven permeation(GDP)and plasma-driven permeation(PDP)of hydrogen gas through Ga In Sn/Fe are systematically investigated in this work.The permeation parameters of hydrogen through Ga In Sn/Fe,including diffusivity,Sieverts'constant,permeability,and surface recombination coefficient are obtained.The permeation flux of hydrogen through Ga In Sn/Fe shows great dependence on external conditions such as temperature,hydrogen pressure,and thickness of liquid Ga In Sn.Furthermore,the hydrogen permeation behavior through Ga In Sn/Fe is well consistent with the multilayer permeation theory.In PDP and GDP experiments,hydrogen through Ga In Sn/Fe satisfies the diffusion-limited regime.In addition,the permeation flux of PDP is greater than that of GDP.The increase of hydrogen plasma density hardly causes the hydrogen PDP flux to change within the test scope of this work,which is due to the dissolution saturation.These findings provide guidance for a comprehensive and systematic understanding of hydrogen isotope recycling,permeation,and retention in plasma-facing components under actual conditions.
基金National Key Research,Development Program of China(No.2017YFE0301305KYWX-002)Sichuan Science and Technology Program(No.2021YFSY0015)Institutional Research Fund from Sichuan University(No.2020SCUNL211)。
文摘Self-cleaning of tin contaminants was realized utilizing a self-driven hydrogen plasma.Cleaning rates of 0.7-6 nm min-1were achieved for removal of discontinuous tin particles at different powers.The analysis of topography and cross-sectional morphology revealed that the removal of tin particles was achieved through top-down cleaning with hydrogen plasma,where the upper part of spherical tin particles was always more intensely cleaned under the synergistic effect of hydrogen atoms and ions due to the vertical incidence of ions to the substrate during the whole cleaning process.Redeposition of tin atoms caused by physical sputtering and its promotion of the chemical cleaning effect was observed for the first time.Reflectance recovery measurements during cleaning and surface analysis of the substrate after cleaning indicated that nondestructive cleaning with a reflectance loss of less than 1%can be achieved at a relatively low power of120 W.Plasma-induced substrate damage,such as holes and valleys,reduced the reflectance of the substrate when cleaning was performed at a high power greater than 120 W,so this method should only be considered for application under conditions without substrate exposure.This study provides a comprehensive understanding of the removal of discontinuous tin particles using the in situ self-driven plasma cleaning method,and also provides meaningful guidance for the extension of this method in other potential fields of application.
基金supported by National Natural Science Foundation of China(Nos.11875198 and 11905151)China Postdoctoral Science Foundation(No.2019M663487)Sichuan Science and Technology Program(Nos.2021YJ0510 and 2021YFSY0015).
文摘This study examined the effects of plasma irradiation on an unwetted liquid lithium-based capillary porous system(Li-CPS). The Li-CPS was irradiated with high-density Ar plasma using a linear plasma device at Sichuan University for Plasma Surface Interaction. The high-speed camera, Langmuir probe, and multi-channel spectrometer were used to characterize the effects of plasma irradiation. Upon Ar plasma irradiation, liquid Li drops were formed on the surface of the unwetted Li-CPS. Immediately after this irradiation, the drops fractured and were ejected into the plasma within ~20 ms scale, which is not observed before to the best of our knowledge. Related results showed that the ejection behavior of Li could effectively cool electron temperature and reduce incident heat flux by ~30% and correspondingly matrix temperature ~150 ℃, revealing an enhanced vapor shielding effect. The involved internal mechanism and physical processes deserve further investigations.
基金funded by National Key Research, Development Program of China (No. 2017YFE0301305KYWX-002)Sichuan Science and Technology Program (No. 2021YFSY0015)
文摘Atmospheric pressure plasma jet(APPJ)was used to clean nitrogen-containing carbon films(C–N)fabricated by plasma-assisted chemical vapor deposition method employing the plasma surface interaction linear device at Sichuan University(SCU-PSI).The properties of the contaminated films on the surface of pristine and He-plasma pre-irradiated tungsten matrix,such as morphology,crystalline structure,element composition and chemical structure were characterized by scanning electron microscopy,grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy.The experimental results revealed that the removal of C–N film with a thickness of tens of microns can be realized through APPJ cleaning regardless of the morphology of the substrates.Similar removal rates of 16.82 and 13.78μm min^(-1)were obtained for C–N films deposited on a smooth pristine W surface and rough fuzz-covered W surface,respectively.This is a remarkable improvement in comparison to the traditional cleaning method.However,slight surface oxidation was found after APPJ cleaning,but the degree of oxidation was acceptable with an oxidation depth increase of only 3.15 nm.Optical emission spectroscopy analysis and mass spectrometry analysis showed that C–N contamination was mainly removed through chemical reaction with reactive oxygen species during APPJ treatment using air as the working gas.These results make APPJ cleaning a potentially effective method for the rapid removal of C–N films from the wall surfaces of fusion devices.
基金by National Natural Science Foundation of China(No.11875198)Young Scientists Fund of National Natural Science Foundation of China(No.11905151)+1 种基金Fundamental Research Funds for the Central Universities of China(No.2019SCU12072)the China Postdoctoral Science Foundation(No.2019M663487).
文摘The net erosion yield of CX-2002U carbon fiber composites under high-flux low-temperature hydrogen plasma is investigated using a linear plasma device.It is found that the net erosion yield decreases rapidly first,and then tends to saturate with the increase of hydrogen–plasma flux.When the temperature of the sample eroded by hydrogen plasma is above 300°C,the hybridization of electrons outside the carbon atom would change.Then the carbon atoms combine with hydrogen atoms to form massive spherical nanoparticles of hydrocarbon compounds and deposit on the surface at the flux condition of 1.77×10^(22) m^(−2)·s^(−1).Under the irradiation of hydrogen plasma loaded with negative bias,the surface morphology of the matrix carbon is changed dramatically.Moreover,the energy dependence of mass loss does not increase in proportion to the increase of hydrogen–plasma energy,but reaches a peak around 20 V negative bias voltage.Based on the analysis of different samples,it can be concluded that the enhancement of energy could make a contribution to chemical erosion and enlarge the size of pores existing on the surface.
基金Project supported by the Sichuan Provincial Science and Technology Program,China(Grant Nos.2021YFSY0015and 2021YJ0510)the China Postdoctoral Science Foundation(Grant No.2019M663487)the National Natural Science Foundation of China(Grant No.11905151)。
文摘Steady high-flux helium(He)plasma with energy ranging from 50 eV to 90 eV is used to fabricate a fiber-form nanostructure called fuzz on a polycrystalline molybdenum(Mo)surface.Enhanced hydrogen(H)pulsed plasma in a wide power density range of 12 MW/m^(2)-35 MW/m^(2)is subsequently used to bombard the fuzzy Mo,thereby simulating the damage of edge localized mode(ELM)to fuzz.The comparisons of surface morphologies,crystalline structures,and optical reflectivity between the original Mo and the Mo treated with various He^(+)energy and transient power densities are performed.With the increase of He ion energy,the Mo nano-fuzz evolved density is enlarged due to the decrease of filament diameter and optical reflectivity.The fuzz-enhanced He release should be the consequence of crystalline growth and the lattice shrinkage inside the Mo-irradiated layers(^(2)00 nm).The fuzz induced by lower energy experiences more severe melting damage and dust release under the condition of the identical transient H plasma-bombardment.The H and He are less likely to be trapped due to aggravated melting evidenced by the enhanced crystalline size and distinct lattice shrinkage.As the transient power density rises,the thermal effect is enhanced,thereby causing the fuzz melting loss to aggravate and finally to completely disappear when the power density exceeds 21 MW/m^(2).Irreversible grain expansion results in huge tensile stress,leading to the observable brittle cracking.The effects of transient thermal load and He ion energy play a crucial role in etching Mo fuzz during ELM transient events.
