Faculty Profiles - UMEHARA, Noritsugu

Papers - UMEHARA, Noritsugu

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Investigating running-in behavior to understand wear behavior of ta-C coating with filtered cathodic vacuum arc deposition Reviewed International coauthorship International journal

Lee W.Y., Tokoroyama T., Murashima M., Umehara N.

Jurnal Tribologi Vol. 23 page： 38 - 47 2019

Language：English Publishing type：Research paper (scientific journal) Publisher：Jurnal Tribologi

In this study, to clarify running-in cycle and role of carbon transfer layer on wear, ta-C coatings were subjected to friction tests under 200 °C in air with a different sliding cycles. The steady state friction coefficient of 0.02 was obtained after finishing a running-in cycles approximately 2,000 cycles. During the steady state, wear rate of ta-C decreased with increasing number of cycles. Such the decrease of wear rate was explained by polished defects presented on surface and form carbon transfer layer on the counter-part material. The mechanism of those tribological properties was analyzed by Raman spectroscopy, scanning electron microscope observation and 3D measuring laser microscope.

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The tribological potential of graphene growth from solid waste Reviewed International coauthorship International journal

Tahir N.A.M., Abdollah M.F.B., Tamaldin N., Amiruddin H., Zin M.R.B.M., Tokoroyama T., Umehara N.

Progress in Industrial Ecology Vol. 13 ( 4 ) page： 401 - 413 2019

Language：English Publishing type：Research paper (scientific journal) Publisher：Progress in Industrial Ecology

This study aimed to identify the tribological potential of graphene growth from solid waste products on copper substrate via the chemical vapour deposition method. The study focused on graphene growth from fruit cover plastic waste (FCPW) and oil palm fibre (OPF), the graphene structure was zexamined using Raman spectroscopy. Then, the tribological testing was performed using a ball-on-disc tribometer, and the hardness was performed using a nano-indenter on both the worn and unworn surfaces. The results show that graphene was successfully grown from both sources. Meanwhile, the tribological study found that both coatings showed a higher coefficient of friction (μ) compared to pure copper. However, the wear rate (k) was contradicted by the μ where the k was found to be 60% to 75% lower than pure copper. Finally, the hardness analysis revealed that the coating was damaged at 100 m sliding as the surface hardness increased.

DOI： 10.1504/PIE.2019.102864

Scopus

Effect of Carbon Diffusion on Friction and Wear Behaviors of Diamond-Like Carbon Coating Against Cr-Plating in Boundary Base Oil Lubrication Reviewed International journal

Aboua Kouami Auxence Melardot, Umehara Noritsugu, Kousaka Hiroyuki, Tokoroyama Takayuki, Murashima Motoyuki, Mabuchi Yutaka, Higuchi Tsuyoshi, Kawaguchi Masahiro

Tribology Online Vol. 13 ( 5 ) page： 290 - 300 2018.12

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

Investigations on tribological behaviors of Diamond-like Carbon (DLC) coating against other materials are strongly needed for scientific and industrial purposes. Recently, carbon diffusion has been found to play a key role in the wear of hydrogenated amorphous carbon (a-C:H) DLC coating when it is rubbed against steel counterpart material in boundary lubrication. Chromium has been reported to decrease carbon diffusion due to increase of the activation energy. In this research, we investigated on the effects of carbon diffusion on friction and wear properties of a-C:H coating when rubbed against Cr plating material. Results show that compared to steel counterpart, a-C:H coating exhibits lower friction coefficient, lower wear rate, and lower carbon diffusion rate when rubbed against Cr plating counterpart.

DOI： 10.2474/trol.13.290

Scopus

CiNii Research

The Clarification of Friction Mechanism in Oil Lubrication for CNx Coating by In-Situ Observation of Friction Area with Reflectance Spectroscopy Reviewed

OKAMOTO Tatsuya, UMEHARA Noritsugu, MURASHIMA Motoyuki, SAITO Koji, MANABE Kazuyoshi, HAYASHI Keiji

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS Vol. 63 ( 11 ) page： 755 - 767 2018.11

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

To clarify the low friction mechanism of CNx coating in PAO oil lubrication, we measured reflectance spectrum at friction area in-situ by reflectance spectroscopy during friction test against a sapphire hemi-sphere pin in PAO oil. We observed and estimated thickness of PAO oil film, surface roughness of CNx coating, thicknesses and polarizability of transformed layer formed on bulk CNx coating during friction test by analyzing reflectance spectrum. We proposed that the decreasing of load ratio of boundary lubrication mode to total load is the one of governing factor to reduce friction on the basis of the increasing of Λ value. Also we proposed the increasing of adsorption of PAO oil to the CNx transformed layer is the second governing factor on the basis of the increasing of polarizability of PAO oil and transformed layer, that leads to the increasing of van der Waals force between transformed layer and PAO oil as low friction mechanism of CNx in PAO oil lubrication.

DOI： 10.18914/tribologist.17-00023

CiNii Research

Effect of ZnDTP Triboflim's Morphology on Friction Behaviors of DLC Coatings: Tribofilm Characterization by 3D Scanning Electron Microscope Observation Reviewed International coauthorship

K. A. M. Aboua, N. Umehara, H. Kousaka, T. Tokoroyama, M. Murashima, H. Abdullah Tasdemir, Y. Mabuchi, T. Higuchi

Journal of Advanced Mechanical Design, Systems, and Manufacturing Vol. 12 ( 7 ) 2018.11

Deposition of ta-C:B Coating by FCVA Using Boron Doped Target and Its Tribological Behaviors at Elevated Temperature up to 300℃ Reviewed

NEMOTO Kouki, UMEHARA Noritsugu, TOKOROYAMA Takayuki, MURASHIMA Motoyuki, TAKIMOTO Yuji, NAKAMICHI Kenji

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS Vol. 63 ( 10 ) page： 699 - 705 2018.10

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

Boron doped tetrahedral amorphous carbon (ta-C:B) coatings were deposited with Filtered Cathodic Vacuum Arc (FCVA) method using boron doped graphite target (B=0, 5 and 10 at. %). The material properties and tribological properties of ta-C:B coatings were obtained at 23~300℃. The amount of boron contents in ta-C:B coatings are from 0 to 5.1 at. %, and the hardness of coatings ware more than 30 GPa. The friction coefficient of ta-C:B3.1 at 300℃ is about 0.02 in air. The specific wear rate of ta-C:B coating were lower than normal ta-C coating by 34% and 46% for ta-C:B3.1 and ta-C:B5.1, respectively. The sp2/(sp2+ sp3) ratio measured by XPS and O/C ratio measured by AES increased through the friction at 300℃ for ta-C, on the other hand both values did not change for ta-C:B. Friction coefficients of ta-C:B3.1 were shown as 0.055 at 23℃ and about 0.02 at 100~300℃. The specific wear rate of ta-C:B3.1 at 23~300℃ in air was about 2.0 × 10−6 mm3/Nm. From these results, we confirmed that ta-C:B shows lower friction and higher specific wear resistance at 23~300℃ in air than ta-C.

DOI： 10.18914/tribologist.18-00003

CiNii Books

CiNii Research

The effects of oil additives and mating materials to the friction, wear and seizure characteristics of a-C:H coating Reviewed International coauthorship International journal

Mohd Taufik bin Taib, Noritsugu Umehara, Takayuki Tokoroyama, Motoyuki Murashima

JURNAL TRIBOLOGI Vol. 18 page： 1 - 19 2018.9

Language：English Publishing type：Research paper (scientific journal) Publisher：MALAYSIAN TRIBOLOGY SOC-MYTRIBOS

In this study, friction and wear behaviour of amorphous hydrogenated carbon (a-C:H) DLC coating slide against SUJ2, TiC and TiN mating material disks in Base and ZnDTP+MoDTC oils boundary lubrication is comparatively investigated to determine the most favourable DLC/mating material/lubricant and interrelated tribofilm formation mechanism on each mating mating materials. Tribological tests were executed by utilizing roller on disk friction tester, nano-indentation hardness test, 3D optical surface profiler, and EDS-SEM were used to characterize the tribofilm formed on both worn roller and disk surfaces. The results showed that the wear volume of a-C:H/TiC tribo-pair in ZnDTP+MoDTC marked a tremendous wear volume reduction compared to than that of in Base oil. EDS investigation on tribofilm element investigation revealed that SUJ2 and TiN mating material disk attracted high concentration of Molybdenum at% on its surface that later caused high wear volume on both roller and disk sliding surfaces. TiC mating material disk however, formed a low at% yet helpful tribofilm consisting of a fraction of Zn phosphate from ZnDTP attached on both roller and disk which assisted the reduction of wear volume.

Web of Science

The Effect of UV Irradiation to a-C:H on Friction and Wear Properties under PAO Oil Lubrication Including MoDTC and ZnDTP Reviewed International journal

bin Taib Mohd Taufik, Umehara Noritsugu, Tokoroyama Takayuki, Murashima Motoyuki

Tribology Online Vol. 13 ( 3 ) page： 119 - 130 2018.7

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

One of the solutions to reduce friction between two sliding surfaces in automobile engine is by applying DLC coating to engine components. However, it is critical that the effect of lubricant additives to DLC coating to be clarified before hands as to avoid components failure. In this study, tribological friction test between SUJ2 balls and as-deposited plus UV irradiated a-C:H coatings was conducted to clarify the effect of ultraviolet irradiation to DLC coating in four different additives added lubricant oils. AFM, nano-indentation hardness test, ellipsometery, Zygo, and EDS-SEM were used to investigate the effect of UV irradiation to a-C:H DLC before and after friction test. Prior the friction test, the results showed that UV irradiation presented no significant change in terms of hardness and roughness but the irradiation did penetrate into topmost surface of the a-C:H coating to several degree and created dangling bonds available to interact with lubricant additives elements. Friction test results showed that UV irradiated a-C:H coatings presented lower friction coefficient than as deposited a-C:H coatings. Worn surface analysis revealed that UV irradiated a-C:H coatings attracted more lubricant additives element to attach on its surface thus created thicker tribofilm on its own surface and its counter materials, resulted in lower friction coefficient than the as-deposited a-C:H coatings.

DOI： 10.2474/trol.13.119

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CiNii Research

Chemical modification at and within nanopowders: Synthesis of core-shell Al2O3@TiON nanopowders via nitriding nano-(TiO2)(0.43)(Al2O3)(0.57) powders in NH3 Reviewed International coauthorship International journal

You Fei, Sun Kai, Yi Eongyu, Nakatani Eitaro, Umehara Noritsugu, Laine Richard M

JOURNAL OF THE AMERICAN CERAMIC SOCIETY Vol. 101 ( 4 ) page： 1441 - 1452 2018.4

Effect of nanoparticles as lubricant additives on friction and wear behavior of tetrahedral amorphous carbon (ta-C) coating Reviewed

Li Xiang, Murashima Motoyuki, Umehara Noritsugu

JURNAL TRIBOLOGI Vol. 16 page： 15-29 2018.3

Effect of nanoparticles as lubricant additives on friction and wear behavior of tetrahedral amorphous carbon (ta-C) coating Reviewed International coauthorship International journal

Li Xiang, Murashima Motoyuki, Umehara Noritsugu

JURNAL TRIBOLOGI Vol. 16 page： 15-29 2018.3

Effect of Substrate Bias and Temperature on Friction and Wear Properties for ta-C Coating Prepared under Different Substrate Bias Voltages with Filtered Cathodic Vacuum Arc Deposition Reviewed International coauthorship International journal

Lee Woo-Young, Tokoroyama Takayuki, Jang Young-Jun, Umehara Noritsugu

Tribology Online Vol. 13 ( 5 ) page： 241 - 247 2018

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

In this paper, the tribological behaviors of 1 μm of tetrahedral amorphous carbon (ta-C) coatings deposited with a different substrate bias of -0 V, -100 V and -300 V are examined under elevated temperature up to 600°C. It is found that wear behavior could be divided into two distinct regions according to testing temperature. The variation trend of the specific wear rate of ta-C coatings in region I at 23, 100 and 200°C are affected by abrasive particles which coincide with sp3 content of ta-C coatings. In region II at 300, 400 and 500°C, the transfer layer play a major role in reduction of wear rate as a function of substrate bias.

DOI： 10.2474/trol.13.241

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CiNii Research

Collecting micrometer-sized wear particles generated between DLC/DLC surfaces under boundary lubrication with an electric field

TOKOROYAMA Takayuki, KAMIYA Toru, AFMAD Nazeef Afifi Bin Hafiz, UMEHARA Noritsugu

Mechanical Engineering Letters Vol. 4 ( 0 ) page： 18-00089 - 18-00089 2018

Language：English Publisher：The Japan Society of Mechanical Engineers

Carbonaceous coatings such as Diamond-Like Carbon (DLC) are attractive candidates for reducing friction under boundary lubrication. However, the wear particles generated from the DLC are believed to form hard slurries that scratch surfaces like an abrasive, and they can shorten the lifetime of the DLC itself. Generally, in conventional automobiles, these wear particles are collected by oil filters. Modern engine bearings are required to reduce the friction coefficient to low levels so that low-viscosity lubricants are used to reduce resistance to flow. However, using a low-viscosity lubricant result in direct solid contact between surfaces, which disrupts the hydrodynamic lubrication and generates numerous wear particles. In this study, we carried out friction tests between DLC/DLC surfaces with kerosene as a boundary lubricant at room temperature. The friction tests were conducted over 12,000 cycles, and we replaced the lubricant after every 2000 cycles without changing the contact pair. Wear particles were collected from the lubricant using an electric field with the electrophoresis effect. The wear particles gathered near the positive electrode and fell onto a glass plate. Finally, after the kerosene evaporated, scanning electron microscope and laser optical microscope observations showed the relations between particle size and shape, the number of wear particles, and the friction coefficient.

DOI： 10.1299/mel.18-00089

CiNii Research

Effect of ZnDTP triboflim's morphology on friction behaviors of DLC coatings: Tribofilm characterization by 3D scanning electron microscope observation Reviewed International journal

ABOUA Kouami Auxence Melardot, UMEHARA Noritsugu, KOUSAKA Hiroyuki, TOKOROYAMA Takayuki, MURASHIMA Motoyuki, TASDEMIR Haci Abdullah, MABUCHI Yutaka, HIGUCHI Tsuyoshi

Journal of Advanced Mechanical Design, Systems, and Manufacturing Vol. 12 ( 7 ) page： JAMDSM0129 - JAMDSM0129 2018

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

ZnDTP antiwear additive for lubricating oil is known to absorb strongly on sliding surfaces in boundary lubricated tribosystems, forming a tribofilm, which is able to reduce the wear of involved surfaces. It is also known to increase the friction coefficient in most DLC/DLC contacts, with the exception of ta-C DLC / ta-C DLC contact, for which the difference in friction behaviors between a base oil + ZnDTP additive lubricated tribosystem and a base oil lubricated tribosystem is not very significant. In this study we investigate a characterization method of the shape of the tribofilm formed on different types of DLC coatings and on the relation between the shape of the tribofilm and the friction behavior of the related DLC coating. Results show that compared to other investigated DLC types, the tribofilm formed on ta-C DLC has some unique characteristic topography features that promote lower friction coefficient.

DOI： 10.1299/jamdsm.2018jamdsm0129

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CiNii Research

Comparative study on effects of load and sliding distance on amorphous hydrogenated carbon (a-C:H) coating and tetrahedral amorphous carbon (ta-C) coating under base-oil lubrication condition Reviewed

Xiang Li, Xingrui Deng, Hiroyuki Kousaka, Noritsugu Umehara

Wear Vol. 392 page： 84 - 92 2017.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Elsevier Ltd

In this study, the lubricated friction and wear associated with diamond-like coatings (DLCs) of amorphous hydrogenated carbon (a-C:H) and hydrogen-free tetrahedral amorphous carbon (ta-C) were comparatively analyzed. The effects of load and sliding distance on the wear and friction behaviors of the coatings were studied under a boundary-lubrication condition using a poly-alpha-olefin base oil. The DLC-coated cylindrical specimens were slid with their central axes perpendicular to the sliding direction against a rotating steel counterface. The results show that the friction coefficient of the ta-C coating was lower than that of the a-C:H coating, though a graphitized layer was detected both inside and outside the wear scar of the a-C:H coating. Under a relatively low applied load (5 N), the specific wear rate of the ta-C coating was considerably lower than that of the a-C:H coating. When the load was increased to a critical value of 10 N, the specific wear rate of the ta-C coating increased rapidly to 3–5 times that of the a-C:H coating. However, the specific wear rate of the a-C:H coating decreased significantly when the load exceeded 10 N, which was consistently maintained thereafter. With the increase in the sliding distance, the specific wear rate of the ta-C coating increased rapidly. In comparison to the ta-C coating, the specific wear rate of the a-C:H coating decreased only slightly with the increase in the sliding distance
moreover, when the sliding distance exceeded 125 m, the specific wear rate of the a-C:H coating became much lower than that of the ta-C coating. The results of Raman spectroscopy, atomic force microscopy, and scanning electron microscopy show that the coatings were influenced by different types of wear mechanisms when slid under pure base-oil boundary-lubrication conditions.

DOI： 10.1016/j.wear.2017.09.009

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Effect of mating materials on wear properties of amorphous hydrogenated carbon (a-C:H) coating and tetrahedral amorphous carbon (ta-C) coating in base oil boundary lubrication condition Reviewed International journal

Li Xiang, Sawaki Toshiya, Kousaka Hiroyuki, Murashima Motoyuki, Umehara Noritsugu

JURNAL TRIBOLOGI Vol. 15 page： 1-20 2017.12

Effect of oil temperature and counterpart material on the wear mechanism of ta-CNx coating under base oil lubrication Reviewed

Xiaoxu Liu, Ryo Yamaguchi, Noritsugu Umehara, Motoyuki Murashima, Takayuki Tokoroyama

WEAR Vol. 390-391 page： 312 - 321 2017.11

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

Tetrahedral amorphous carbon nitride (ta-CNx), as an emerging and promising diamond-like carbon (DLC), has better mechanical properties than amorphous carbon nitride (a-CNx) to ensure the sufficient durability, and overcomes the limit of high internal stress of tetrahedral amorphous carbon (ta-C), which makes ta-CNx coatings of great worth of research for the tribological and mechanical applications. In this study, we present the effects of oil temperature and counterpart material on the wear behavior of ta-CNx coatings under base-oil lubrication, and further clarify the wear mechanism. ta-C and ta-CNx coatings with N/C atomic ratio of 2.2% and 11.0% were deposited by an ion beam assisted filtered arc deposition (IBA-FAD) system, and the tribological tests were performed using a ball-on-disk tribo-tester with ta-C and ta-CNx coated steel ball sliding against uncoated disk under base-oil lubrication. The results show that nitrogen doping tends to decrease the hardness and Young's modulus by reducing the sp(3) structure. Sliding against steel disk, with increase of sliding distance ta-CNx shows obviously distinct wear behavior compared to ta-C, much more slowly increasing wear volume, exhibiting excellent wear resistance. Increasing oil temperature from room temperature to 120 degrees C results in rising wear rates of all the three coatings, with totally worn out ta-C and much lower wear rate of ta-CNx, which decreases by more than half than ta-C for high nitrogen content ta-CNx. However, as the counterpart material changed from steel to alumina, the wear rate presents oppositely increasing tendency with N/C ratio, probably caused by the change of deciding factor to hardness in this mechanical wear. It is found that the wear performance of ta-CNx coating has a clear dependence on the oil temperature and counterpart material. Based on the results, the better wear resistance of softer ta-CNx against steel could be attributed to the less tribo-chemical wear between carbon and iron, due to the nitrogen doping partial passivation effect.

DOI： 10.1016/j.wear.2017.08.012

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Scopus

Effect of carbon diffusion on friction and wear properties of diamond-like carbon in boundary base oil lubrication Reviewed International journal

Kouami Auxence Melardot Aboua, Noritsugu Umehara, Hiroyuki Kousaka, Xingrui Deng, Haci Abdullah Tasdemir, Yutaka Mabuchi, Tsuyoshi Higuchi, Masahiro Kawaguchi

Tribology International Vol. 113 page： 389 - 398 2017.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Ltd

In order to control wear and friction in industry, Diamond like carbon (DLC) hard coatings are widely applied in recent years due to their well appreciated mechanical and tribological properties. However, those properties are not yet well understood, as well as behavior of DLC hard coatings when rubbed against other materials. Other researchers reported that DLC hard coatings film show high wear when rubbed against steel counterpart and their durability decrease with the increase of the temperature. In this research, we investigated on friction and wear properties of DLC coatings and the results reveal that carbon diffusion has a key role in the wear and friction behavior of DLC coatings when rubbed against steel.

DOI： 10.1016/j.triboint.2016.10.047

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Clarification of effect of transformed layer and oil film on low friction coefficient of CNx coating in PAO oil lubrication by in-situ observation of friction area with reflectance spectroscopy Reviewed

Hidenori Nishimura, Noritsugu Umehara, Hiroyuki Kousaka, Motoyuki Murashima

TRIBOLOGY INTERNATIONAL Vol. 113 page： 383 - 388 2017.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

In order to clarify a low friction mechanism of CNx (Carbon Nitride) coating in PAO (Poly Alpha Olefin) oil lubrication, we measured reflectance spectrum at friction area in-situ by reflectance spectroscopy. And we obtained thicknesses and polarizabilities of oil film and transformed layer formed on bulk CNx coating during friction test by analyzing reflectance spectrum. From results, we concluded that the increments of polarizabilities of transformed layer and oil film had an effect on increasing thickness of oil film, and then the lubricated condition changed from boundary to mixed lubrication. Finally CNx coating showed low friction coefficient in PAO oil lubrication.

DOI： 10.1016/j.triboint.2016.10.029

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The effects of temperature, pressure and dissolved oxygen concentration (DO) in water on the wear of the hydrogenated diamond-like carbon (HDLC) at high temperature and pressurized water Reviewed

Mohd Rody Bin Mohamad Zin, Yuji Yagi, Keiji Sasaki, Naruhiko Inayoshi, Takayuki Tokoroyama, Noritsugu Umehara, Hiroyuki Kousaka, Shingo Kawara

Tribology International Vol. 109 page： 48 - 57 2017.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Ltd

The aim of this study is to clarify the wear mechanism of hydrogenated diamond-like carbon (HDLC) coating in high temperature and pressurized water. A new reciprocating autoclave wear tester was developed to conduct the wear test between DLC coated pins against SUS316 plate in high temperature and pressurized water. The results showed that the wear of HDLC in water was greatly influenced by water temperature from 23 °C to 300 °C and dissolved oxygen concentration (DO) from 0.73 mg O/L to 47.5 mg O/L (mg O/L:milligrams oxygen per liter) in water. On the other hand, water pressure in the chamber did not have significant effect on the wear of HDLC when pressure was increased from 10 MPa to 30 MPa at 300 °C. Based on surface analysis by XPS, AFM nano scratch, Raman spectroscopy, and AES on the top most surface of the wear scar of HDLC, softening and oxidation of top layer of wear scar of HDLC was found to be the mechanisms of high wear of HDLC in high temperature and pressurized water. The transformation of sp3 to sp2 at higher water temperature is believed to be responsible for the reduced hardness of the top most surface of HDLC. Oxidation also provided softening of top layer of HDLC at higher DO in water.

DOI： 10.1016/j.triboint.2016.12.010

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Papers - UMEHARA, Noritsugu