研究者業績

八重 真治

ヤエ シンジ  (Shinji Yae)

基本情報

所属
兵庫県立大学 大学院 工学研究科 化学工学専攻 教授
学位
博士(工学)(大阪大学)
工学修士(大阪大学)

ORCID ID
 https://orcid.org/0000-0003-1181-4811
J-GLOBAL ID
200901050293971558
researchmap会員ID
1000029997

外部リンク

論文

 177
  • Naoki Fukumuro, Takeshi Kinoshita, Tomoya Hashimoto, Shinji Yae
    Journal of the Japan Institute of Metals and Materials 88(10) 233-238 2024年10月1日  
  • Yuna IWAI, Ayumu MATSUMOTO, Yumi TAKASHIMA, Shinji YAE
    Electrochemistry 92(8) 087001-087001 2024年8月1日  
  • Kyohei Azuma, Ayumu Matsumoto, Rin Nishinaka, Shinji Yae
    Journal of The Electrochemical Society 171(6) 062505-062505 2024年6月3日  
    Metal-assisted etching (metal-assisted chemical etching) is an efficient method to fabricate porous silicon (Si). When using platinum (Pt) particles as metal catalysts in metal-assisted etching, a composite porous structure of straight macropores formed beneath the Pt particles and a mesoporous layer formed on the entire surface of Si can be fabricated. The formation mechanism of the composite structure is still open to discussion. We previously demonstrated that the ratio of mesoporous layer thickness to macropore depth showed a large value (approximately 1.1) in the case of highly-doped p-Si. In this study, we investigated the composite structure formation by using p-Si substrates with different doping densities and etching solutions with different concentrations of hydrogen peroxide (H2O2). There was not significant difference in the structures formed on low- and moderately-doped Si, despite the large difference in doping density. The ratio of mesoporous layer thickness to macropore depth increased within the range approximately from 0.1 to 0.4 with increasing the H2O2 concentration in the case of low- and moderately-doped Si, but it did not change in the case of highly-doped Si. We discussed the observation results based on the spatial distribution of hole consumption and the band structures at Pt/Si and Si/electrolyte interfaces.
  • Koichiro NISHIZAWA, Ayumu MATSUMOTO, Yasuyuki NAKAGAWA, Hitoshi SAKUMA, Yoshiki KOJIMA, Naoki FUKUMURO, Shinji YAE
    Electrochemistry 2024年  
  • Ayumu Matsumoto, Yuta Toyama, Yusuke Shimazu, Keisuke Nii, Yoshiaki Ida, Shinji Yae
    Journal of Analytical Atomic Spectrometry 39(10) 2532-2542 2024年  
    This is the first report that applied LIBS to the analysis of electropolishing solution. Quantitative analysis of Nb dissolved in the solution was demonstrated by using porous silicon as the sample loading substrate.
  • Shinji Yae, Yuna Iwai, Yumi Takashima, Takumi Osaka, Ayumu Matsumoto
    ECS Meeting Abstracts 2023年12月22日  
  • Shinji Yae, Ayumu Matsumoto, Naoki Fukumuro
    Journal of the Society of Powder Technology, Japan 60(12) 739-747 2023年12月10日  
  • Ryota Saida, Tomohiro Shimizu, Takeshi Ito, Yukihiro Tominari, Shukichi Tanaka, Naoki Fukumuro, Shinji Yae, Shoso Shingubara
    Journal of Electronic Materials 52(10) 6690-6698 2023年7月26日  
  • Koichiro Nishizawa, Ayumu Matsumoto, Yasuyuki Nakagawa, Hitoshi Sakuma, Seiki Goto, Naoki Fukumuro, Shinji Yae
    Journal of Electronic Materials 52(6) 4080-4090 2023年6月  
    The thermal stability of electroless nickel-phosphorus (Ni-P) film and cobalt-tungsten–phosphorus (Co-W-P) film deposited on GaAs substrate was investigated. X-ray photoelectron spectroscopy and x-ray diffraction measurements indicated that the Ni-P film changed from amorphous to crystalline by annealing at 240°C for 1 h due to the diffusion of Ni into the GaAs substrate and the increase in P concentration in the Ni-P film. On the other hand, the crystallinity of the Co-W-P film did not change by annealing at 240°C for 1 h. Cross-sectional observation showed that the thickness of the crystallized Ni-P film did not change from 3 to 1000 h of high-temperature storage at 270°C, and no void was observed in the Ni-P film. Migration of Ni atoms could be suppressed by the crystallization of the Ni-P film. On the other hand, voids were formed in the Co-W-P film after high-temperature storage at 270°C for 100 h. Since the Co-W-P film consists of nanoscale crystalline and amorphous phases, atoms diffuse from the amorphous portion to the GaAs substrate. Graphical Abstract: [Figure not available: see fulltext.].
  • Ayumu Matsumoto, Rin Nishinaka, Yuki Shimada, Kyohei Furukawa, Kyohei Azuma, Shinji Yae
    Journal of The Electrochemical Society 170(5) 052505-052505 2023年5月1日  
    Platinum (Pt) is one of the interesting catalysts in metal-assisted etching (metal-assisted chemical etching) of silicon (Si). The Pt-assisted etching induces not only the dissolution of Si under the Pt catalysts but also the formation of mesoporous layer on the Si surface away from them. In this work, we etched n-Si and p-Si by using patterned Pt films with a diameter of 5 μm and an interval of 50 μm. For both the cases, the Si surface under the Pt catalysts was selectively etched and macropores with a diameter of 5 μm were formed. The macropores formed on n-Si were deeper than those formed on p-Si. The mesoporous layer was observed only around the macropores on n-Si, while it was observed over the entire surface of p-Si. We also measured the open circuit potential of Si in the etching solution. The positive shift of potential of n-Si by the Pt deposition was smaller than that of p-Si except for the initial stage of etching, which can be explained by the polarization characteristics. We discussed the etching behavior of n-Si and p-Si on the basis of the results of structure observation and electrochemical measurements.
  • Ayumu MATSUMOTO, Yusuke SHIMAZU, Shinji YAE
    Journal of The Surface Finishing Society of Japan 74(4) 198-202 2023年4月1日  
  • Ayumu Matsumoto, Yusuke Shimazu, Shinji Yae, Tetsuo Sakka
    Journal of Analytical Atomic Spectrometry 38(12) 2590-2597 2023年  
    Strong correlations were found between underwater LIBS signals and bubble collapse time. Signal fluctuation caused by the repeated irradiation at a fixed position was successfully reduced by the normalization with bubble collapse time.
  • Ryutaro Miura, Tomoya Hashimoto, Kazuhiro Fukami, Naoki Fukumuro, Shinji Yae, Kuniaki Murase
    MATERIALS TRANSACTIONS 2023年  
  • Tsuyoshi Fujino, Naoki Fukumuro, Vijay Chouhan, Muneaki Ida, Yoshiaki Ida, Shinji Yae
    Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals 87(1) 18-23 2023年  
    The effect of electropolishing conditions on the outgassing properties of austenitic stainless steel (SUS316L) electropolished by a wiping method (WiEP) and an immersion method (ImEP) was investigated using thermal desorption spectroscopy. In the case of electropolishing by the WiEP in which the metal surface was wiped with an electrolyte–solution–impregnated felt wiper cathode, the SUS316L surface became smoother and the amount of outgassing decreased as the applied voltage (4–8 V) increased. In the case of electropolishing by the ImEP, the SUS316L surface became smoother and the amount of outgassing decreased as the current density (8–15 A dm−2) increased. After electropolishing by the WiEP at higher applied voltages and the ImEP at higher current densities, diffusible hydrogen desorbed from the SUS316L surface below 723 K was almost completely removed, however most of the non–diffusible hydrogen remained. These results suggest that the migration of diffusible hydrogen to the SUS316L surface is enhanced by the increase in the applied voltage of electropolishing. [doi:10.2320/jinstmet.J2022032]
  • Tsuyoshi Fujino, Naoki Fukumuro, Vijay Chouhan, Muneaki Ida, Yoshiaki Ida, Shinji Yae
    Journal of Vacuum Science and Technology B 40(6) 2022年12月1日  
    Surface and outgassing properties of 304 stainless steel samples were studied after electropolishing by a wiping method (WiEP) using felt that is attached to a cathode electrode and impregnated with an electrolyte. Surface morphology observed with an atomic force microscope suggests that WiEP yields a smoother surface with fewer pits compared with the conventional electropolishing method of immersing the samples in an electrolyte. The thickness of the oxide layer after either of the electropolishing processes was 3-4 nm as estimated by x-ray photoelectron spectroscopy, transmission electron microscopy, and energy-dispersive x-ray spectroscopy. Furthermore, no significant difference was found in the chemical state of the surface and oxide film in the two cases. Thermal desorption spectroscopy of the samples revealed that the amount of desorbed H2O and H2 was significantly low in the case of WiEP. The low outgassing was attributed to the formation of a smooth and dense oxide film on the sample surface after electropolishing by WiEP.
  • Naoki Fukumuro, Kosuke Tohda, Shinji Yae
    Journal of the Electrochemical Society 169(12) 2022年12月  
    The existing states of co-deposited hydrogen in copper films electrolessly deposited from an ethylenediaminetetraacetatic acid complex bath were investigated using thermal desorption spectroscopy. Small desorption peaks at 500-700 K and large desorption peaks at 900-1300 K were observed in the as-deposited copper film, and these were attributed to the break-up of vacancy-hydrogen clusters and the desorption of molecular hydrogen from nanovoids, respectively. Moreover, an unknown desorption peak appeared at around 390 K. The total amount of desorbed hydrogen from the copper film in atomic ratio was 1.2 × 10−2, most of which was non-diffusible hydrogen desorbed above 800 K. A large number of nanovoids distributed in the grains were observed in the copper film. After 7 days, no significant change in hydrogen desorption above 500 K was observed, while the unknown desorption peak around 390 K disappeared. The as-deposited copper film showed lattice expansion and compressive residual stress, which were reduced after 7 days. Therefore, we attributed the unknown desorption peak appearing at around 390 K to the desorption of hydrogen atoms trapped by regular interstitial sites in the copper lattice.
  • Yusuke Shimazu, Ayumu Matsumoto, Sachiyo Hirai, Haruka Nakano, Kosuke Suzuki, Shinji Yae
    Spectrochimica Acta - Part B Atomic Spectroscopy 197 2022年11月  
    Porous silicon (Si) produced by metal-assisted etching using nanoparticles (Si nanohole array with straight pores) has potential as a sample loading substrate of laser-induced breakdown spectroscopy (LIBS). In this work, we investigated the characteristics of laser-induced plasma generated on the porous Si with different pore depths (pore depth: approximately 180, 320, and 990 nm) from spectroscopic aspects. The intensity of Si I line was enhanced by using the porous Si instead of a flat Si, it increased with increasing the pore depth of porous Si, and its enhancement factor reached 45 (pore depth: approximately 990 nm). The atomic excitation temperature and atomic number density increased with increasing the pore depth, whereas the intensity ratio of Si II line to Si I line and the intensity of nitrogen I line decreased. These results provide an insight into the plasma formation on nanomaterials.
  • Ayumu Matsumoto, Kyohei Azuma, Kyohei Furukawa, Rin Nishinaka, Shinji Yae
    Journal of the Electrochemical Society 169(10) 2022年10月  
    Electroless deposition of metal particles on silicon (Si) followed by the metal-assisted etching (metal-assisted chemical etching) is a simple way to fabricate Si nanostructures. A composite porous structure consisting of straight macropores and a mesoporous layer can be created by platinum (Pt)-particle-assisted etching. In this work, we studied the composite structure formation on a highly-doped p-Si (ca. 5 × 1018 cm−3) in comparison with a moderately-doped p-Si (ca. 1 × 1015 cm−3). The composite structure drastically changed: the ratio of mesoporous layer thickness to macropore depth increased to 1.1 from 0.16 by using the highly-doped Si instead of the moderately-doped Si. The open circuit potential of Si in the etching solution shifted to the positive direction by the Pt deposition. The potential shift of highly-doped Si was smaller than that of moderately-doped Si, which can be explained by the polarization characteristics. We calculated the band bending in Si by using a device simulator that reproduced the conditions of Pt-particle-assisted etching. The results indicated that, in the case of highly-doped Si, the consumption rate of positive holes at the Si surface away from the Pt particles increases due to the tunneling effect, which is consistent with the thick mesoporous layer formation.
  • Ayumu MATSUMOTO, Yumi TAKASHIMA, Yuna IWAI, Shinji YAE
    Journal of The Surface Finishing Society of Japan 73(9) 456-458 2022年9月1日  
  • Yuna IWAI, Ayumu MATSUMOTO, Shinji YAE
    Journal of The Surface Finishing Society of Japan 73(6) 295-299 2022年6月1日  
  • Yumi TAKASHIMA, Ayumu MATSUMOTO, Yuna IWAI, Shotaro ARITA, Shinji YAE
    Journal of The Surface Finishing Society of Japan 73(2) 98-102 2022年2月1日  査読有り最終著者
  • Tomoya Hashimoto, Tomoya Nakamura, Naoki Fukumuro, Shinji Yae
    Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals 86(9) 172-175 2022年  
    The structural changes in electrodeposited palladium (Pd) films with desorption of co–deposited hydrogen were investigated, and the existing states of hydrogen in the Pd film were analyzed. The Pd films were electrodeposited from an alkaline bath consisted of palladium (II) chloride, ammonium chloride, and citric acid. Two pronounced desorption peaks at around 500 K and 880 K were observed in the thermal desorption spectrum of hydrogen from as–deposited Pd film. For the Pd films with lower hydrogen concentrations, the lattice contraction proceeded concurrently with hydrogen desorption at room temperature. The lattice parameter of Pd film decreased with increasing heat treatment temperature up to 500 K, and then increased with grain growth above 550 K. An exothermic peak corresponding to the hydrogen desorption at around 500 K was observed in the differential scanning thermal analysis curve. A large number of nano–voids were observed in the Pd film. These results suggested that the hydrogen desorption peaks observed at around 500 K and 880 K were ascribed to the break–up of vacancy–hydrogen clusters and the desorption of hydrogen molecules from nano–voids, respectively.
  • Naoki Fukumuro, Kohei Sawada, Shinji Yae
    Keikinzoku/Journal of Japan Institute of Light Metals 72(6) 482-484 2022年  
    In this study, hydrogen incorporated into 7075 aluminum alloy substrates by electroless Ni-P plating was investigated. In the cross-sectional transmission electron microscope images, a low phosphorus content (5.7mass%) film consisted of fine grains and a high phosphorus content (12.1mass%) film consisted of an amorphous phase were observed on the 7075 alloy substrates. Depth profile analysis by glow discharge optical emission spectrometry revealed that the intensity of hydrogen increased in the 7075 alloy substrate after electroless Ni-P plating, and was higher at the interface between the Ni-P film and the 7075 alloy substrate. In the thermal desorption spectra of hydrogen from the 7075 alloy substrates with low and high phosphorous content Ni-P films, a pronounced desorption peak and a series of desorption peaks were observed. Such desorption peaks were not observed in the 7075 alloy substrate before electroless Ni-P plating and in the Ni-P films on the copper substrates. These results indicate that the hydrogen incorporated into the 7075 alloy substrate by electroless Ni-P plating exists in various trap sites such as interstitial sites, vacancies, grain boundaries, and the incoherent interface between the precipitates and the aluminum basal phase.
  • Ryohei Shinno, Makoto Hino, Ryoichi Kuwano, Koji Monden, Masaaki Sato, Yukinori Oda, Naoki Fukumuro, Shinji Yae, Keitaro Horikawa, Teruto Kanadani
    Materials Transactions 63(6) 872-876 2022年  
    In this study, A2017-T4 aluminum alloy was plated with electroless NiP with different phosphorus content and rotary bending fatigue test was conducted to investigate the effect of hydrogen by plating on fatigue properties. The fatigue strength of the low-phosphorus type NiP plated specimen was higher than that of the untreated specimen, while that of the high-phosphorus type plated specimen was much lower. It is clear that the fatigue strength differs greatly depending on the phosphorus content in the plating film. The decrease in fatigue strength of the high phosphorus type plating specimen was attributed to hydrogen induced by plating from hydrogen analysis. Thus, despite the previous report that 2000 series aluminum alloys do not exhibit hydrogen embrittlement in slow strain rate tensile tests under wet condition, it was found that A2017-T4 aluminum alloy undergo hydrogen embrittlement when the alloy is plated with high-phosphorus type electroless NiP and fatigue-tested on rotary bending machine.
  • Ryohei Shinno, Makoto Hino, Ryoichi Kuwano, Koji Monden, Masaaki Sato, Yukinori Oda, Naoki Fukumuro, Shinji Yae, Keitaro Horikawa, Teruto Kanadani
    Materials Transactions 63(12) 1617-1621 2022年  
    In this study, with the aim of improving the fatigue characteristics of the A7075 aluminum alloy, A7075-T6511 alloy rod specimens were plated with electroless NiP with different compositions, and the fatigue characteristics were evaluated by a rotary bending fatigue test. The fatigue strength of the specimen plated with low-P type was higher than that of the un-plated specimen. However, the fatigue strength of the specimen plated with high-P type was significantly lower than that of the un-plated specimen, and the fatigue strength of the specimen plated with medium-P type was also lower though the extent was not so significant. It was speculated that these reductions in fatigue strength were due to hydrogen embrittlement by the hydrogen introduced into the specimen during the plating.
  • Kouji Maeda, Masato Moritoki, Shinji Yae, Keisuke Fukui, Naoki Fukumuro, Takeshi Sugahara
    Physical Chemistry Chemical Physics 24(22) 14085-14091 2022年  
    We found that an AAA-type battery (min. 750 mAh) pressurized with Ar or N2 at pressures of up to 5 MPa exhibited a significant durability enhancement even under high-current conditions.
  • Makoto HINO, Ryoichi KUWANO, Norihito NAGATA, Michiru YAMASHITA, Naoki FUKUMURO, Ayumu MATSUMOTO, Shinji YAE, Kazuya NAGATA, Tsukasa SONODA, Teruto KANADANI
    Journal of The Surface Finishing Society of Japan 72(12) 713-715 2021年12月1日  査読有り
  • Kouji Maeda, Shinji Yae, Naoki Fukumuro, Kenji Iimura, Ayumu Matsumoto
    Journal of The Electrochemical Society 168(12) 120511-120511 2021年12月1日  査読有り
    A nickel-metal hydride (Ni–MH) prototype battery completely immersed in an aqueous electrolyte solution of KOH under high-pressure was fabricated to examine the effects of high-pressure on the quality of Ni–MH batteries. The small battery cell comprised positive and negative electrode materials, as used in electric vehicles, and an Ag/AgO reference electrode. The electric capacity of the Ni–MH battery was measured at different temperatures and pressures with small currents and charge/discharge voltages of 1.6–1.0 V. High-pressure was found to clearly and effectively enhance the electric capacity of the Ni–MH battery at larger currents. The considerable effect of high-pressure on the Ni–MH battery was elucidated by the change in internal resistance during the charge/discharge cycle life experiment, indicating that the voltage of the positive electrode did not appreciably change under high-pressure compared to that of the negative electrode. Moreover, the use of large currents in rapid charge/discharge cycle tests at high pressures of up to 30 MPa resulted in charge/discharge cycles that were five times faster and a quick recovery of capacity was achieved in the 0.5–2.1 V range.
  • Ayumu Matsumoto, Kyohei Furukawa, Shun Majima, Keishi Iwamoto, Shinji Yae
    Journal of The Electrochemical Society 168(11) 112504-112504 2021年11月1日  査読有り最終著者
  • Yusuke SHIMAZU, Ayumu MATSUMOTO, Haruka NAKANO, Shinji YAE
    Analytical Sciences 37(12) 1839-1841 2021年6月  査読有り最終著者
  • Ayumu Matsumoto, Yusuke Shimazu, Haruka Nakano, Kento Murakami, Shinji Yae
    Spectrochimica Acta Part B: Atomic Spectroscopy 178 106143-106143 2021年4月  査読有り最終著者
  • Ayumu MATSUMOTO, Keishi IWAMOTO, Yuki SHIMADA, Kyohei FURUKAWA, Shun MAJIMA, Shinji YAE
    Electrochemistry 89(2) 125-130 2021年3月5日  査読有り最終著者
  • Ryohei Shinno, Makoto Hino, Ryoichi Kuwano, Koji Monden, Masaaki Sato, Yukinori Oda, Naoki Fukumuro, Shinji Yae, Keitaro Horikawa, Teruto Kanadani
    Keikinzoku/Journal of Japan Institute of Light Metals 71(10) 450-454 2021年  査読有り
    In this study, A2017-T4 aluminum alloy was plated with electroless Ni-P with different phosphorus content and rotary bending fatigue test was conducted to investigate the effect of hydrogen by plating on fatigue properties. The fatigue strength of the low-phosphorus type Ni-P plated specimen was higher than that of the untreated specimen, while that of the high-phosphorus type plated specimen was much lower. It is clear that the fatigue strength differs greatly depending on the phosphorus content in the plating film. The decrease in fatigue strength of the high phosphorus type plating specimen was attributed to hydrogen induced by plating from hydrogen analysis. Thus, despite the previous report that 2000 series aluminum alloys do not exhibit hydrogen embrittlement in slow strain rate tensile tests under wet condition, it was found that A2017-T4 aluminum alloy undergo hydrogen embrittlement when the alloy is plated with high-phosphorus type electroless Ni-P and fatigue-tested on rotary bending machine. (Received May 19, 2021 Accepted August 15, 2021)
  • Ryohei Shinno, Makoto Hino, Ryoichi Kuwano, Koji Monden, Masaaki Sato, Yukinori Oda, Naoki Fukumuro, Shinji Yae, Keitaro Horikawa, Teruto Kanadani
    Keikinzoku/Journal of Japan Institute of Light Metals 71(12) 534-538 2021年  査読有り
    In this study, with the aim of improving the fatigue characteristics of the A7075 aluminum alloy, A7075-T6511 alloy rod specimens were plated with electroless Ni-P with different compositions, and the fatigue characteristics were evaluated by a rotary bending fatigue test. The fatigue strength of the specimen plated with low-P type was higher than that of the un-plated specimen. However, the fatigue strength of the specimen plated with high-P type was significantly lower than that of the un-plated specimen, and the fatigue strength of the specimen plated with medium-P type was also lower though the extent was not so significant. It was speculated that these reductions in fatigue strength were due to hydrogen embrittlement by the hydrogen introduced into the specimen during the plating.
  • Takuji Yamamoto, Yuichiro Yoshida, Shogo Taguchi, Naoki Fukumuro, Shinji Yae, Kazuhiro Itoh, Kouji Maeda
    MATEC Web of Conferences 333 11010-11010 2021年  査読有り
    <jats:p>We attempted to recover phosphorus species from a waste plating solution of electroless nickel-phosphorus plating. With the aim of increasing the recovery yield by oxidizing phosphite to phosphate efficiently, we examined ozonation of a model plating solution by supplying ozonecontaining oxygen gas to the solution employing an aerated mixing vessel. As a result of the measurements of the transient changes in the concentrations of the phosphorus species and dissolved ozone in the solution, we confirmed the effect of the organic additives contained in the plating solution on the ozonation efficiency. Calcium chloride was subsequently added to the ozone-treated solution to precipitate the phosphate as calcium hydrogen phosphate, which was poorly soluble to water. At this moment, the recovery yield of the phosphorus from the model waste plating solution was greater than 86%.</jats:p>
  • 福田健二, 藤居 稜, 髙坂祐一, 山田直輝, 松本 歩, 八重真治
    表面技術 71(12) 839-841 2020年12月1日  査読有り最終著者責任著者
  • Naoki Fukumuro, Kosuke Tohda, Shinji Yae
    ECS Meeting Abstracts 2020年11月23日  
  • Shinji Yae, Ayumu Matsumoto
    ECS Meeting Abstracts 2020年11月23日  
  • Kuge, T., Nishimoto, T., Kurohagi, M., Maeda, K., Yae, S., Mukouyama, Y.
    Electrochemistry 88(3) 157-164 2020年5月5日  査読有り
  • Naoki FUKUMURO, Shinji YAE
    Journal of The Surface Finishing Society of Japan 71(5) 314-322 2020年5月1日  
  • Matsumoto, A., Shimazu, Y., Yoshizumi, S., Nakano, H., Yae, S.
    Journal of Analytical Atomic Spectrometry 35(10) 2239-2247 2020年  査読有り最終著者
    <p>The LIBS signal of the dry residue from a small amount of liquid sample is significantly enhanced by using a porous silicon substrate produced by gold-nanoparticle-assisted etching.</p>
  • Yokohama, H., Tayakout-Fayolle, M., Galfré, A., Fukumuro, N., Yae, S., Maeda, K., Yamamoto, T.
    ACS Omega 5(12) 6937-6946 2020年  査読有り
    In electroless nickel-phosphorus plating (ENPP), growth of the plated layer under high pressure was found to be faster than under ambient pressure. To quantitatively elucidate the effect of high pressure on the mechanism of the ENPP reaction, we propose a kinetic model that takes into account both mass transfer and reaction of the chemical species present in the plating solution. We solved the mass balance equations between the chemical species to calculate the transient changes in the thickness of the plated layer as well as the concentrations of the chemical species in the plating solution. By fitting the calculated results to the experimentally acquired results based on the nonlinear least square method, we determined such parameters as the film mass transfer coefficient, the adsorption constants, and the reaction rate constants of the chemical species in the model. As a result, we found that the film mass transfer coefficient under high pressure was greater than that under ambient pressure and revealed the dependence of the coefficient on pressure. The transient changes in the concentrations of the chemical species in the plating solution that we calculated based on the kinetic model employing our estimated parameters closely modeled the experimental results with the determination coefficients being mostly over 99%.
  • Fukumuro, N., Fukai, Y., Sugimoto, H., Ishii, Y., Saitoh, H., Yae, S.
    Journal of Alloys and Compounds 825 2020年  査読有り最終著者
    © 2020 Elsevier B.V. Superstoichiometric hydrides PdHx have been synthesized by the electrochemical method. The H concentrations, x = H/Pd = 1.13–1.97, have been determined directly by thermal desorption. From X-ray diffraction, the structure is found to be face-centered cubic, with the lattice parameter changing smoothly over the concentration range, x = 0.7–2.0. Surprisingly, however, the lattice parameter goes through a maximum at x ∼1.0 and decreases at higher concentrations. It is suggested from electronic and Monte Carlo calculations that these unique features of the structure and formation process should be the consequence of partial replacement of Pd atoms with H2, namely, the formation of superabundant vacancies filled with H2 molecules.
  • Migita, T., Kobune, M., Ito, R., Obayashi, T., Kikuchi, T., Fujisawa, H., Kanda, K., Maenaka, K., Nishioka, H., Fukumuro, N., Yae, S.
    Japanese Journal of Applied Physics 59(SC) accepted-SCCB10 2020年  査読有り
  • Ayumu Matsumoto, Hikoyoshi Son, Makiho Eguchi, Keishi Iwamoto, Yuki Shimada, Kyohei Furukawa, Shinji Yae
    RSC advances 10(1) 253-259 2020年1月  査読有り最終著者
  • Tatsuya Takemoto, Naoki Fukumuro, Shinji Yae, Hitoshi Matsuda
    ECS Transactions 33(21) 11-15 2019年12月17日  査読有り
    The objective of this study is to reveal the atomistic state of hydrogen in electrodeposited Ni-P films by thermal desorption spectroscopy. Two peaks corresponding to the desorption of hydrogen occupying regular interstitial sites and the break-up of vacancy-hydrogen (Vac-H) clusters were observed in electrodeposited pure Ni film. With an increase in phosphorus content, the crystallinity of electrodeposited Ni-P films decreased and the hydrogen desorption from the interstitial sites and Vac-H clusters disappeared. The amount of diffusible hydrogen increased abruptly with the increase in the amorphous phase in Ni-P film. ©The Electrochemical Society.
  • Ayumu Matsumoto, Hironori Ohba, Masaaki Toshimitsu, Katsuaki Akaoka, Alexandre Ruas, Ikuo Wakaida, Tetsuo Sakka, Shinji Yae
    Spectrochimica Acta - Part B Atomic Spectroscopy 155 56-60 2019年5月  査読有り最終著者
    © 2019 Elsevier B.V. Fiber-optic laser-induced breakdown spectroscopy (LIBS) can be used for on-site chemical analysis in harsh environments with a flexible light delivery system. In this work, the use of a long-pulse laser (100 ns) is proposed for the detection of molecular emission signals, instead of a normal-pulse laser (6 ns). We show a significant enhancement of AlO signals using an aluminum metal target in air. We also elucidate the enhancement mechanism of the AlO formation by measuring species-specific images of the emission from aluminum atoms, oxygen atoms, and AlO molecules in the plasma. The internal structure of the plasma suggests that the formation origin of AlO molecules in the long-pulse-produced plasma is essentially different from that in the normal-pulse-produced plasma. The long-pulse laser causes a rise of the ablation plume and facilitates the flow of oxygen from the ambient air. This is a key factor to enhance the molecular emission signals.
  • 小田幸典, 相良優作, 福室直樹, 八重真治
    表面技術 70(3) 163-167 2019年3月1日  査読有り最終著者責任著者
  • 髙坂祐一, 藤居 稜, 山田直輝, 福室直樹, 阪本 進, 松本 歩, 八重真治
    表面技術 70(3) 174-176 2019年3月1日  査読有り最終著者責任著者

主要なMISC

 341

講演・口頭発表等

 16

担当経験のある科目(授業)

 8

主要な共同研究・競争的資金等の研究課題

 17