Faculty Profiles - TSUKIYAMA Yosuke

Papers - TSUKIYAMA Yosuke

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Clarification of hysteresis mechanism in the indentation of the high-densed carbon nanotube film Reviewed

Masaharu Wakayama, Yosuke Tsukiyama, Takayuki Tokoroyama, Hiroyuki Kousaka, Noritsugu Umehara

Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C 79 ( 801 ) 1821 - 1826 2013

Language：Japanese Publishing type：Research paper (scientific journal)

The Carbon Nanotubes have been reported to show hysteresis curves by Nano-indentation tests. To clarify the mechanism of this hysteresis, we conducted Nano-indentation tests to CNT films by using two diamond tips with different curvature radii. The AFM Nano-indentation was to perform penetration of diamond tip into CNT film, which means generation of friction force between diamond tip aspect and CNT tubes aspect. On the other hand, in the case of using spherical diamond tip by which cyclic Nano-indentation tests were conducted, the load-displacement curves became similar to those of carbonaceous coatings. This means that cyclic indentation for CNT made it like continues material. However, after several cyclic Nano-indentation tests to same position, the CNT specimen still showed hysteresis curve. These results indicated that hysteresis of CNT by Nano-indentation was related to friction between CNT tubes each other. © 2013 The Japan Society of Mechanical Engineers.

DOI： 10.1299/kikaic.79.1821

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Characteristics of the transformed layer of DLC after friction testing under boundary lubrication in additive-free mineral based oil

Nor Azmmi Bin Masripan, Yosuke Tsukiyama, Kenji Ohara, Noritsugu Umehara, Hiroyuki Kousaka, Takayuki Tokoroyama, Shigeru Inami, Koji Zushi

5th World Tribology Congress, WTC 2013 1 646 - 649 2013

Evaluation of Sealing Characteristics of High-Performance Gasket Using a Laser Microscope with Wide Field of View

Yoshio Matsuzaki, Isami Nitta, Yosuke Tsukiyama

17th ISC (International Sealing Conference) 329 - 338 2012.9

Effects of Paper Debris on Micro-Slip Characteristics of Rubber Rollers

Isami Nitta, Tsuyoshi Tsukada, Yosuke Tsukiyama

ITC Hiroshima 2011 2011.11

The Influence of Interlayer for Frictional Property and Adhesion of IBAD CNx Coating Reviewed

Masaharu WAKAYAMA, Yosuke TSUKIYAMA, Takayuki TOKOROYAMA, Hiroyuki KOUSAKA, Noritsugu UMEHARA, Mei WANG, Takaomi TOIHARA

Transactions of the Japan Society of Mechanical Engineers. C 77 ( 781 ) 3502 - 3510 2011.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers

The carbonaceous hard coating such as Diamond-Like Carbon is one of the materials to prevent surface damage. It was reported that Carbon Nitride (CNx) coating showed superlow friction coefficient when it slid against a Si3N4 ball in N2 environment. In the case of applying CNx coating for industrial fields, it is necessary to improve adhesion between CNx coating and substrate. In this study, we clarify the effect of interlayer to improve adhesion of CNx coating to WC substrate. 4 different kinds of interlayer materials were prepared. From the scratching test results, adhesion of using CrN and no interlayer was smallest. On the other hand, SiN, CN and DLC interlayers showed high adhesion. From the finite element analysis, interlayer thickness and Young's modulus did not affect to improve adhesion between CNx coating and WC substrate.

DOI： 10.1299/kikaic.77.3502

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Review on Japanese-German-US Cooperation on Laser-Ablation Propulsion Reviewed

Stefan Scharring, John E. Sinko, Stephanie Karg, Hans-Albert Eckel, Hans-Peter Roeser, Akihiro Sasoh, Naoya Ogita, Noritsugu Umehara, Yosuke Tsukiyama

BEAMED ENERGY PROPULSION: SEVENTH INTERNATIONAL SYMPOSIUM 1402 47 - 61 2011

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

We report on an international cooperation between Nagoya University (NU), Japan and DLR Stuttgart, Germany on scaling issues in laser ablative propulsion. Lessons learned from collaborative work in the laboratory will be summarized with respect to the comparability of experimental methods and corresponding standardization issues. With the background of previous experimental research at the University of Alabama in Huntsville (UAH), experimental work with CO2 lasers in a moderate (NU) and high (DLR) pulse energy range on laser ablation of POM is presented. Profilometry results of target surfaces are compared with fluence distributions from beam propagation modeling. Ablation from flat targets is reported with respect to energy and area scaling and compared with results from ablative propulsion employing parabolic nozzles.

DOI： 10.1063/1.3657015

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Nanowear Characteristics of Carbon Nanotube Film Made by Surface Decomposition of SiC Reviewed

Yosuke Tsukiyama, Noritsugu Umehara, Michiko Kusunoki

JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 4 ( 1 ) 373 - 382 2010

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN SOC MECHANICAL ENGINEERS

This paper shows the wear characteristics of carbon nanotube films made by surface decomposition of SiC. By this method, one can obtain remarkably high density of CNTs with well vertical alignment. For the purpose of measuring the wear characteristics of CNT films with submicrometer thickness, we carried out nanoscratch and nanoindentation tests by using an atomic force microscope (AFM). And we used 2 kinds of AFM cantilever tips with tip radii of about 20 nm and 150 nm. The experimental results showed wear behaviors of CNT films dependent on CNT length and normal load. And CNT films were worn gradually as the number of wear cycles increased. The effect of CNT length on wear of CNT films appeared as different behaviors of CNT films under normal load. That was originated from bending stiffness of each CNTs with different length as measured by nanoindentation. Shorter-CNT films had less wear because of higher deformation resistance than longer ones. Under the normal load, the SCD tip penetrated to several tens of nanometers in depth, but the CNT films showed only wear depth on the order of angstrom for each scratch cycle. Thus we confirmed that CNT films have both strength and flexibility, which reflects remarkable mechanical properties of CNTs. These results are important for machine designs using CNT films as friction materials.

DOI： 10.1299/jamdsm.4.373

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Critical Fluences And Modeling Of CO2 Laser Ablation Of Polyoxymethylene From Vaporization To The Plasma Regime Reviewed

John E. Sinko, Claude R. Phipps, Yosuke Tsukiyama, Naoya Ogita, Akihiro Sasoh, Noritsugu Umehara, Don A. Gregory

BEAMED ENERGY PROPULSION 1230 395 - + 2010

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

A CO2 laser was operated at pulse energies up to 10 J to ablate polyoxymethylene targets in air and vacuum conditions. Critical effects predicted by ablation models are discussed in relation to the experimental data, including specifically the threshold fluences for vaporization and critical plasma formation, and the fluence at which the optimal momentum coupling coefficient is found. Finally, we discuss a new approach for modeling polymers at long wavelengths, including a connection formula that links the vaporization and plasma regimes for laser ablation propulsion.

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CO2 Laser Ablation Propulsion Area Scaling With Polyoxymethylene Propellant Reviewed

John E. Sinko, Katsuhiro Ichihashi, Yosuke Tsukiyama, Naoya Ogita, Takeharu Sakai, Noritsugu Umehara, Akihiro Sasoh

BEAMED ENERGY PROPULSION 1230 207 - + 2010

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

The topic of area scaling is of great importance in the laser propulsion field, including applications to removal of space debris and to selection of size ranges for laser propulsion craft in air or vacuum conditions. To address this issue experimentally, a CO2 laser operating at up to 10 J was used to irradiate targets. Experiments were conducted in air and vacuum conditions over a range of areas from about 0.05-5 cm(2) to ablate flat polyoxymethylene targets at several fluences. Theoretical effects affecting area scaling, such as rarefaction waves, thermal diffusion, and diffraction, are discussed in terms of the experimental results. Surface profilometry was used to characterize the ablation samples. A CFD model is used to facilitate analysis, and key results are compared between experimental and model considerations. The dependence of key laser propulsion parameters, including the momentum coupling coefficient and specific impulse, are calculated based on experimental data, and results are compared to existing literature data.

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Evaluation of mechanical properties of the superficial layer of CNx with ultra low friction in N2 gas Reviewed

Norihiro Kimura, Yosuke Tsukiyama, Takayuki Tokoroyama, Noritsugu Umehara

Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C 76 ( 772 ) 3794 - 3799 2010

Language：Japanese Publishing type：Research paper (international conference proceedings) Publisher：Japan Society of Mechanical Engineers

Carbon nitride (CNx) coating is one of the carbonaceous materials, which was reported to show superlow friction coefficient (μ&lt
0.009) in Nitrogen environment. Therefore CNx coating is a promising material of solid lubricant for sliding interfaces to reduce friction. The superlow friction appeared after running in process of several hundreds of friction cycles and its mechanism has not been completely clarified yet. It was proposed that the soft thin layer generated on CNx coating after running-in process contributed to the superlow friction. However, the mechanical properties of the superficial layer of CNx coating such as hardness and Young's modulus have not been experimentally shown because of its small thickness estimated to be 10 nm or less. So we carried out in-depth measurements of mechanical properties of the thin layer on CNx film by nanoscratching test using an atomic force microscope. Then the existence of thin, soft layer on the top of CNx coating after running-in process was experimentally shown.

DOI： 10.1299/kikaic.76.3794

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CO2 Laser Ablation Area Scaling And Redeposition On Flat Polyoxymethylene Targets Reviewed

John E. Sinko, Stefan Scharring, Yosuke Tsukiyama, Katsuhiro Ichihashi, Naoya Ogita, Akihiro Sasoh, Noritsugu Umehara, Hans-Albert Eckel, Hans-Peter Roeser

INTERNATIONAL SYMPOSIUM ON HIGH POWER LASER ABLATION 2010 1278 538 - + 2010

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

One of the remaining unknown subjects of laser propulsion involves whether special benefits or challenges exist for applying laser ablation propulsion to targets with particularly large or small spot areas. This subject is of high importance for a wide range of topics ranging from laser removal of space debris to micropropulsion for laser propulsion vehicles. Analysis is complex since different ablation phenomena are dominant between atmosphere and vacuum conditions. Progress has also been impeded by the difficulty of setting control parameters (particularly fluence) constant while the spot area is adjusted. It is also usually difficult for one group to address small- and large-area effects using a single high-power laser system. Recent collaborative experiments on laser ablation area scaling at several institutions, using 100-J class and 10-J class CO2 lasers, have advanced the understanding of laser propulsion area scaling. The spot area-dependence of laser propulsion parameters has been investigated over an area range covering approximately 0.05-50 cm(2) at low fluence of about 0.6 J/cm(2). The experiments were conducted well below the threshold for plasma formation, and provide an estimate of the ablation threshold for CO2 laser ablation of POM.

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T1602-2-4 Measurement of Shearing Stress of the Topmost Layer of Carbon Nitride Coating by AFM

TSUKIYAMA Yosuke, KIMURA Norihiro, TOKOROYAMA Takayuki, UMEHARA Noritsugu

The proceedings of the JSME annual meeting 2010 231 - 232 2010

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Carbon nitride (CNx) coating is one of the carbonaceous materials, which was reported to show superlow friction coefficient (μ<0.009) in Nitrogen environment. Therefore CNx coating is a promising material of solid lubricant for sliding interfaces to reduce friction. The superlow friction appeared after running in process of several hundreds of friction cycles and its mechanism has not been completely clarified yet. It was proposed that the soft thin layer generated on CNx coating after running-in process contributed to the superlow friction. However, the shearing strength of the superficial layer of CNx coating has not been experimentally shown because of its small thickness estimated to be 10 nm or less. So we carried out in-depth measurements of the friction force of CNx film against a cantilever tip by nanoscratching test using an atomic force microscope. Then the existence of thin, low-shear layer on the top of CNx coating after running-in process was experimentally shown.

DOI： 10.1299/jsmemecjo.2010.8.0_231

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Strength at the Interface of CNT Films Made by Surface Decomposition of SiC（共著） Reviewed

Yosuke Tsukiyama, Noritsugu Umehara, Michiko Kusunoki

Tribology Online 3 ( 7 ) 352 - 355 2008.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Tribologists

Adherence of carbon nanotube film made by surface decomposition of SiC was studied. For this purpose we carried out scratch tests in nano- and microscale. By microscratch test, it was found that adherence at the interface was higher for CNT films with shorter CNTs and CNTs were not broken at the middle but removed from the interface. To clarify the dominant force (shear force or moment of force) which caused different adherence, we also carried out nanoscratch test by using AFM. In nanoscratch, AFM tip made of diamond coated silicon applied shear force to CNT films from lateral direction. And there was no significant change of adherence by lateral force (shear force at the interface). We conclude that bending-induced moment of force is dominant on the interface strength of CNT films.

DOI： 10.2474/trol.3.352

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Precision blanking of thin sheet metals with the help of chemical etching Reviewed

K. Hirota, Y. Tsukiyama, T. Yasuumi

JOURNAL OF MATERIALS PROCESSING TECHNOLOGY 201 ( 1-3 ) 209 - 213 2008.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

It is difficult to separate small parts precisely from thin sheet metals by press blanking. This study describes a countermeasure to the problem by combining press forming and chemical etching. A 0.1 mm beryllium copper sheet was indented along a cut profile and subjected to etching, resulting in separation of the part surrounded by the indented line. Etching time to complete separation was considerably reduced compared with the ordinary etching process. Shape of indented portion also affected the etching time. Two indenting methods were tested in combination with two masking methods. SEM observation showed that every test condition provided a good cut edge having a smooth and fracture-free surface although some thickness reduction or dissolution of the cut edge occurred depending on masking methods. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jmatprotec.2007.11.135

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Papers - TSUKIYAMA Yosuke