The Experts below are selected from a list of 41925 Experts worldwide ranked by ideXlab platform

Kazuaki Wagatsuma - One of the best experts on this subject based on the ideXlab platform.

  • surface nitriding treatment of steels using microwave induced Nitrogen Plasma at atmospheric pressure
    Applied Surface Science, 2012
    Co-Authors: Shigeo Sato, Yuuki Arai, Noboru Yamashita, Atsushi Kojyo, Kenji Kodama, Naofumi Ohtsu, Yukio Okamoto, Kazuaki Wagatsuma
    Abstract:

    Abstract A rapid surface-nitriding system using microwave-induced Nitrogen Plasma at atmospheric pressure was developed for modifying iron and steel surfaces. Since the conventional Plasma nitriding technique requires a low-pressure atmosphere in the treatment chamber, the population of excited Nitrogen molecules in the Plasma is limited. Accordingly, several hours are required for nitriding treatment. By contrast, the developed nitriding system can use atmospheric-pressure Plasma through application of the Okamoto cavity for excitation of Nitrogen Plasma. The high population of excited Nitrogen molecules induced by the atmospheric-pressure Plasma allowed the formation of a nitriding layer that was several micrometers thick within 1 min and produced an expanded austenite iron phase with a high Nitrogen concentration close to the solubility limit on the iron substrate. In addition, the nitriding treatment on high-chromium steel was performed by introducing a reducing gas such as NH 3 and H 2 into the treatment chamber. While the nitriding reaction did not proceed in a simple N 2 atmosphere due to surface oxidation, the surface reduction induced by the NH 3 or H 2 gas promoted the nitriding reaction at the surface. These nitriding phenomena characteristics of the atmospheric-pressure Plasma are discussed in this paper based on the effects of the specimen temperature and Plasma atmosphere on the thickness, the chemical states, and the nitride compounds of the nitrided layer as investigated by X-ray diffraction, glow-discharge optical emission spectroscopy, and X-ray photoelectron spectroscopy.

Alenka Vesel - One of the best experts on this subject based on the ideXlab platform.

  • XPS characterization of PTFE after treatment with RF oxygen and Nitrogen Plasma
    Surface and interface analysis, 2016
    Co-Authors: Anton Zalar, Miran Mozetic, Alenka Vesel
    Abstract:

    A study on surface modification of extended PTFE (polytetrafluoroethylene) foil after treatment in oxygen and Nitrogen Plasma is presented. PTFE was exposed to a weakly ionized, highly dissociated RF Plasma with a high density of neutral atoms. The gas pressure was 75 Pa and the discharge power was 200 W. The appearance of the functional groups on the sample surface was determined by using high-resolution XPS. The results showed that oxygen Plasma treatment did not cause any noticeable changes in the surface composition, while after Nitrogen Plasma treatment new functional groups were detected on the surface. Copyright © 2008 John Wiley & Sons, Ltd.

  • Surface modification of polyester by oxygen-and Nitrogen-Plasma treatment
    Surface and interface analysis, 2016
    Co-Authors: Miran Mozetic, Alenka Vesel, Uros Cvelbar, Janez Kovač, Ita Junkar
    Abstract:

    In this paper, we present a study on the surface modification of polyethyleneterephthalate (PET) polymer by Plasma treatment. The samples were treated by Nitrogen and oxygen Plasma for different time periods between 3 and 90 s. The Plasma was created by a radio frequency (RF) generator. The gas pressure was fixed at 75 Pa and the discharge power was set to 200 W. The samples were treated in the glow region, where the electrons temperature was about 4 eV, the positive ions density was about 2 × 1015 m -3, and the neutral atom density was about 4 × 1021 m-3 for oxygen and 1 × 1021 m-3 for Nitrogen. The changes in surface morphology were observed by using atomic force microscopy (AFM). Surface wettability was determined by water contact angle measurements while the chemical composition of the surface was analyzed using XPS. The stability of functional groups on the polymer surface treated with Plasma was monitored by XPS and wettability measurements in different time intervals. The oxygen-Plasma-treated samples showed much more pronounced changes in the surface topography compared to those treated by Nitrogen Plasma. The contact angle of a water drop decreased from 75° for the untreated sample to 20° for oxygen and 25° for Nitrogen-Plasma-treated samples for 3 s. It kept decreasing with treatment time for both Plasmas and reached about 10° for Nitrogen Plasma after 1 min of Plasma treatment. For oxygen Plasma, however, the contact angle kept decreasing even after a minute of Plasma treatment and eventually fell below a few degrees. We found that the water contact angle increased linearly with the O/C ratio or N/C ratio in the case of oxygen or Nitrogen Plasma, respectively. Ageing effects of the Plasma-treated surface were more pronounced in the first 3 days; however, the surface hydrophilicity was rather stable later. Copyright © 2008 John Wiley & Sons, Ltd.

  • Modification of PET surface by Nitrogen Plasma treatment
    Journal of physics Conference series, 2008
    Co-Authors: Miran Mozetic, Alenka Vesel
    Abstract:

    A study on Nitrogen Plasma functionalization of polyethyleneterephthalate (PET) is presented. The samples of PET foils were exposed to a weakly ionized, highly dissociated RF Nitrogen Plasma with an electron temperature of 5 eV, a density of positive ions of the order of 1015 m-3 and a density of neutral Nitrogen atoms of the order of 1021 m -3. The pressure was 75 Pa and a discharge power was 200 W. The PET-samples were exposed to Plasma and its afterglow from 3 s to 10 s. After the treatment the surface was analysed by XPS (X-ray photoelectron spectroscopy). XPS results showed appearance of new functional groups like amine and amide. © 2008 IOP Publishing Ltd.

  • Surface modification of polyester by oxygen‐ and Nitrogen‐Plasma treatment
    Surface and Interface Analysis, 2008
    Co-Authors: Alenka Vesel, Ita Junkar, Uros Cvelbar, Janez Kovač, Miran Mozetic
    Abstract:

    In this paper, we present a study on the surface modification of polyethyleneterephthalate (PET) polymer by Plasma treatment. The samples were treated by Nitrogen and oxygen Plasma for different time periods between 3 and 90 s. The Plasma was created by a radio frequency (RF) generator. The gas pressure was fixed at 75 Pa and the discharge power was set to 200 W. The samples were treated in the glow region, where the electrons temperature was about 4 eV, the positive ions density was about 2 × 1015 m−3, and the neutral atom density was about 4 × 1021 m−3 for oxygen and 1 × 1021 m−3 for Nitrogen. The changes in surface morphology were observed by using atomic force microscopy (AFM). Surface wettability was determined by water contact angle measurements while the chemical composition of the surface was analyzed using XPS. The stability of functional groups on the polymer surface treated with Plasma was monitored by XPS and wettability measurements in different time intervals. The oxygen-Plasma-treated samples showed much more pronounced changes in the surface topography compared to those treated by Nitrogen Plasma. The contact angle of a water drop decreased from 75° for the untreated sample to 20° for oxygen and 25° for Nitrogen-Plasma-treated samples for 3 s. It kept decreasing with treatment time for both Plasmas and reached about 10° for Nitrogen Plasma after 1 min of Plasma treatment. For oxygen Plasma, however, the contact angle kept decreasing even after a minute of Plasma treatment and eventually fell below a few degrees. We found that the water contact angle increased linearly with the O/C ratio or N/C ratio in the case of oxygen or Nitrogen Plasma, respectively. Ageing effects of the Plasma-treated surface were more pronounced in the first 3 days; however, the surface hydrophilicity was rather stable later. Copyright © 2008 John Wiley & Sons, Ltd.

K. Ravi - One of the best experts on this subject based on the ideXlab platform.

  • Surface Modification of Commercial Low-Carbon Steel using Glow Discharge Nitrogen Plasma and its Characterization
    Journal of Materials Engineering and Performance, 2013
    Co-Authors: S. Srikanth, P. Saravanan, Alphonsa Joseph, K. Ravi
    Abstract:

    Plasma nitriding under glow discharge Nitrogen Plasma has been undertaken on laboratory scale for surface engineering of commercial low carbon steels. The treatment has been shown to confer exceptional improvement in surface properties, viz., hardness and corrosion resistance. The results have been discussed in light of microstructural changes occurring on steel surface and its interior as a result of Fickian Nitrogen diffusion and correlated with influences of nitriding-temperature and alloying elements (Mn, Nb, and Si) in steel.

Miran Mozetic - One of the best experts on this subject based on the ideXlab platform.

  • XPS characterization of PTFE after treatment with RF oxygen and Nitrogen Plasma
    Surface and interface analysis, 2016
    Co-Authors: Anton Zalar, Miran Mozetic, Alenka Vesel
    Abstract:

    A study on surface modification of extended PTFE (polytetrafluoroethylene) foil after treatment in oxygen and Nitrogen Plasma is presented. PTFE was exposed to a weakly ionized, highly dissociated RF Plasma with a high density of neutral atoms. The gas pressure was 75 Pa and the discharge power was 200 W. The appearance of the functional groups on the sample surface was determined by using high-resolution XPS. The results showed that oxygen Plasma treatment did not cause any noticeable changes in the surface composition, while after Nitrogen Plasma treatment new functional groups were detected on the surface. Copyright © 2008 John Wiley & Sons, Ltd.

  • Surface modification of polyester by oxygen-and Nitrogen-Plasma treatment
    Surface and interface analysis, 2016
    Co-Authors: Miran Mozetic, Alenka Vesel, Uros Cvelbar, Janez Kovač, Ita Junkar
    Abstract:

    In this paper, we present a study on the surface modification of polyethyleneterephthalate (PET) polymer by Plasma treatment. The samples were treated by Nitrogen and oxygen Plasma for different time periods between 3 and 90 s. The Plasma was created by a radio frequency (RF) generator. The gas pressure was fixed at 75 Pa and the discharge power was set to 200 W. The samples were treated in the glow region, where the electrons temperature was about 4 eV, the positive ions density was about 2 × 1015 m -3, and the neutral atom density was about 4 × 1021 m-3 for oxygen and 1 × 1021 m-3 for Nitrogen. The changes in surface morphology were observed by using atomic force microscopy (AFM). Surface wettability was determined by water contact angle measurements while the chemical composition of the surface was analyzed using XPS. The stability of functional groups on the polymer surface treated with Plasma was monitored by XPS and wettability measurements in different time intervals. The oxygen-Plasma-treated samples showed much more pronounced changes in the surface topography compared to those treated by Nitrogen Plasma. The contact angle of a water drop decreased from 75° for the untreated sample to 20° for oxygen and 25° for Nitrogen-Plasma-treated samples for 3 s. It kept decreasing with treatment time for both Plasmas and reached about 10° for Nitrogen Plasma after 1 min of Plasma treatment. For oxygen Plasma, however, the contact angle kept decreasing even after a minute of Plasma treatment and eventually fell below a few degrees. We found that the water contact angle increased linearly with the O/C ratio or N/C ratio in the case of oxygen or Nitrogen Plasma, respectively. Ageing effects of the Plasma-treated surface were more pronounced in the first 3 days; however, the surface hydrophilicity was rather stable later. Copyright © 2008 John Wiley & Sons, Ltd.

  • Modification of PET surface by Nitrogen Plasma treatment
    Journal of physics Conference series, 2008
    Co-Authors: Miran Mozetic, Alenka Vesel
    Abstract:

    A study on Nitrogen Plasma functionalization of polyethyleneterephthalate (PET) is presented. The samples of PET foils were exposed to a weakly ionized, highly dissociated RF Nitrogen Plasma with an electron temperature of 5 eV, a density of positive ions of the order of 1015 m-3 and a density of neutral Nitrogen atoms of the order of 1021 m -3. The pressure was 75 Pa and a discharge power was 200 W. The PET-samples were exposed to Plasma and its afterglow from 3 s to 10 s. After the treatment the surface was analysed by XPS (X-ray photoelectron spectroscopy). XPS results showed appearance of new functional groups like amine and amide. © 2008 IOP Publishing Ltd.

  • Surface modification of polyester by oxygen‐ and Nitrogen‐Plasma treatment
    Surface and Interface Analysis, 2008
    Co-Authors: Alenka Vesel, Ita Junkar, Uros Cvelbar, Janez Kovač, Miran Mozetic
    Abstract:

    In this paper, we present a study on the surface modification of polyethyleneterephthalate (PET) polymer by Plasma treatment. The samples were treated by Nitrogen and oxygen Plasma for different time periods between 3 and 90 s. The Plasma was created by a radio frequency (RF) generator. The gas pressure was fixed at 75 Pa and the discharge power was set to 200 W. The samples were treated in the glow region, where the electrons temperature was about 4 eV, the positive ions density was about 2 × 1015 m−3, and the neutral atom density was about 4 × 1021 m−3 for oxygen and 1 × 1021 m−3 for Nitrogen. The changes in surface morphology were observed by using atomic force microscopy (AFM). Surface wettability was determined by water contact angle measurements while the chemical composition of the surface was analyzed using XPS. The stability of functional groups on the polymer surface treated with Plasma was monitored by XPS and wettability measurements in different time intervals. The oxygen-Plasma-treated samples showed much more pronounced changes in the surface topography compared to those treated by Nitrogen Plasma. The contact angle of a water drop decreased from 75° for the untreated sample to 20° for oxygen and 25° for Nitrogen-Plasma-treated samples for 3 s. It kept decreasing with treatment time for both Plasmas and reached about 10° for Nitrogen Plasma after 1 min of Plasma treatment. For oxygen Plasma, however, the contact angle kept decreasing even after a minute of Plasma treatment and eventually fell below a few degrees. We found that the water contact angle increased linearly with the O/C ratio or N/C ratio in the case of oxygen or Nitrogen Plasma, respectively. Ageing effects of the Plasma-treated surface were more pronounced in the first 3 days; however, the surface hydrophilicity was rather stable later. Copyright © 2008 John Wiley & Sons, Ltd.

Thad Maloney - One of the best experts on this subject based on the ideXlab platform.

  • Nitrogen Plasma surface treatment for improving polar ink adhesion on micro/nanofibrillated cellulose films
    Cellulose, 2019
    Co-Authors: Katarina Dimic-misic, Bratislav Obradović, Marija Mitrović-dankulov, Stevan Jovanovic, Dimitrije Stepanenko, Ana Kramar, Leena-sisko Johansson, Mirjana Kostic, Saša Lazović, Thad Maloney
    Abstract:

    We find that Nitrogen Plasma treatment of micro/nanofibrillated cellulose films increases wettability of the surface by both liquid polar water and nonpolar hexadecane. The increased wetting effect is more pronounced in the case of polar liquid, favouring the use of Plasma treated micro/nanofibrillated cellulose films as substrates for a range of inkjet printing including organic-based polar-solvent inks. The films were formed from aqueous suspensions of progressively enzymatic pretreated wood-free cellulose fibres, resulting in increased removal of amorphous species producing novel nanocellulose surfaces displaying increasing crystallinity. The mechanical properties of each film are shown to be highly dependent on the enzymatic pretreatment time. The change in surface chemistry arising from exposure to Nitrogen Plasma is revealed using X-ray photoelectron spectroscopy. That both polar and dispersive surface energy components become increased, as measured by contact angle, is also linked to an increase in surface roughness. The change in surface free energy is exemplified to favour the trapping of photovoltaic inks.