研究者詳細 - 梅原　徳次

Evaluation of Mechanical Characteristics of Tribofilm Formed on the Surface of Metal Material Due to Friction under Lubrication with Automatic Transmission Fluid 査読有り国際誌

Tokoroyama Takayuki, Nishimoto Takashi, Murakami Yasuhiro, Honda Akiyuki, Mitsui Hideaki, Terai Yusuke, Murashima Motoyuki, Lee Woo-Young, Umehara Noritsugu

TRIBOLOGY ONLINE 16 巻 ( 4 ) 頁： 255 - 262 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本トライボロジー学会

In this study, nano-scratch tests were conducted using atomic force microscope (AFM) to clarify the hardness of a tribofilm derived from an additive (Fluid A or Fluid B in automatic-transmission fluid) formed on an SKS3 cold work tool steel substrate surface. Comparisons between nano-indentation hardness tests and AFM nano-scratch tests were performed for each specimen. Prior to these tests, the tribofilms on the SKS3 substrate were examined with energy-dispersive spectroscopy (EDS). In order to calculate the hardness of the tribofilm from the nano-scratch results, we assumed that the AFM diamond tip acted as an abrasive to plough the tribofilm. The phosphorous-derived tribofilm formed from Fluid A was harder than the sulfur-derived tribofilm from Fluid B, and it was calculated that the phosphorous-derived tribofilm was approximately 2.64 GPa and the sulfur-derived tribofilm was 1.89 GPa. After 10 nanoindentation hardness tests on each tribofilm, the maximum indentation depth into the tribofilm formed from Fluid A was approximately 31 nm, while it was approximately 36 nm for Fluid B. These results are qualitatively consistent with the hardness results obtained by the AFM nano-scratch test method.

DOI： 10.2474/trol.16.255

The Tribological Properties of Hydrogenated DLC Coating Lubrication with Additive Having Glycerol and Phosphonate Structure 査読有り国際共著国際誌

Kani Takumi, Tokoroyama Takayuki, Umehara Noritsugu, Murashima Motoyuki, Lee Woo-Young, Yagishita Kazuhiro

TRIBOLOGY ONLINE 16 巻 ( 4 ) 頁： 263 - 270 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本トライボロジー学会

In general, several mechanical parts are subjected to friction and wear. To prevent wear and high friction coefficient under lubrication, additives can work to reduce friction force, to build up thin film on surfaces which is so-called tribofilm. Recently, Diamond-Like Carbon (DLC) is focused because it has excellent low friction and high wear proof as solid lubricant. However, several researchers already reported that tetrahedral amorphous carbon (ta-C) showed abnormal wear when it rubbed with glycerol mono-oleate (GMO) that is a kind of additive, although it showed very low friction coefficient. To improve tribological properties, new additives were developed that had both phosphate-oxide structure derived from ZnDTP which had high wear resistance and hydroxy group derived from GMO in one structure. To clarify the effects of the additives, friction tests were performed fixed-roller-on-disk type rotating friction tester. In the friction tests, hydrogenated amorphous carbon (a-C:H) disks, and a-C:H coated rollers were used under boundary lubrication condition at 20-80°C. Friction tests were conducted in Poly-α-olefin (PAO) oil with each GMO and the additives. The results exhibited that a-C:H gave ultra-low friction with the additive. Elemental analysis of the surface showed that tribofilm of phosphorus and oxygen was detected on the a-C:H surface in the additive used condition.

DOI： 10.2474/trol.16.263

New study on tribological performance of AA7075-TiB2 nanocomposites 査読有り国際共著

Pan Shuaihang, Saso Tomohiro, Yu Ning, Sokoluk Maximilian, Yao Gongcheng, Umehara Noritsugu, Li Xiaochun

TRIBOLOGY INTERNATIONAL 152 巻 2020年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Tribology International

AA7075 (Al-Mg-Zn-Cu) nanocomposite is important in tribo-related applications. In this paper, we applied a new method to investigate the coefficient of friction (CoF) of AA7075 (T6)-TiB2 nanocomposite. This method is able to minimize the wear and obtain the CoF values of the nanocomposite. A distinct trend of the CoF is discovered in this study. A novel friction theory with the consideration of surface characteristics, such as hardness difference and atom transfer between friction pairs, has been developed to understand this CoF trend. The new insight from this study offers a great potential for a rational design of AA7075 nanocomposite parts to achieve reliable tribological performance.

DOI： 10.1016/j.triboint.2020.106565

２種混合砥粒研磨法を用いたガラス基板研磨加工による表面粗さ改善速度の向上査読有り

ベース油中CNxの摩擦界面その場反射分光分析観察による摩擦メカニズムの解明招待有り

梅原徳次

トライボロジスト 65 巻 ( 11 ) 頁： 684 - 687 2020年11月

ポリ塩化ビニル溶媒への交流電場援用マイクロプラスチック突起の創製査読有り

山田雄聖，野老山貴行，村島基之，梅原徳次

日本機械学会論文集 86 巻 ( 892 ) 頁： 20-00228 2020年11月

名古屋大学における全学技術支援の一元的組織化招待有り

梅原徳次, 古賀和司, 藤原冨未治, 澤木弘二, 山本浩治, 立花一志, 水口幾久代

精密工学会誌 86 巻 ( 9 ) 頁： 662 - 665 2020年9月

その場摩擦界面反射分光法によるカーボン系硬質膜の摩擦メカニズム招待有り

梅原徳次

表面技術 71 巻 ( 9 ) 頁： 547 - 550 2020年9月

コーティング電気メス先端の炭化物付着抑制手法の開発査読有り

野老山貴行，小林将大，村島基之，梅原徳次，小川航生，萬隆行，内田淳一

日本機械学会論文集 86 巻頁： 20-00273 2020年9月

嶽野広明, 野老山貴行, 村島基之, 梅原徳次, 千葉翔悟

砥粒加工学会誌 64 巻 ( 8 ) 頁： 428 - 435 2020年8月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：社団法人砥粒加工学会

本研究は，ガラス基板研磨における高コストなダイヤモンド砥粒の消費量を削減し，コスト低減と表面粗さの早期改善を目的として低硬度な砥粒とダイヤモンド砥粒を混合した，2種混合砥粒による研磨手法の開発を行った．低硬度砥粒としてGC砥粒の大きさの影響（約127 μm, 75 μmおよび13 μm），砥粒濃度の影響，砥粒種類の影響（WAおよびB4C）を明らかにした．また，砥粒の研磨面内の挙動をその場観察するため，砥粒をロ-ダミンにより蛍光染色して観察を行った．その結果，2種混合砥粒によって表面粗さの低減速度の向上に成功した．また，粒径の大きなGC砥粒は研磨に用いた天然シルク研磨パッドの繊維のすき間に移動あるいは挟みこまれる様子が観察された．一方，平均粒径1.0 μmのダイヤモンド砥粒は天然シルク研磨パッドとガラス基板間を繊維の向きとは無関係に移動している様子が観察された．

DOI： 10.11420/jsat.64.428

CiNii Books

金ナノ粒子法を用いた表面増強ラマン分析による炭素系薄膜の極表面分析査読有り

野老山貴行，梅原徳次，村島基之

トライボロジスト 65 巻 ( 8 ) 頁： 517 - 525 2020年8月

New study on tribological performance of AA7075-TiB2 nanocomposites 査読有り国際共著国際誌

Shualihang Pan, Tomohiro Saso, Ning Yu, Maximillan Sokoluk, Gongcheng Yao, Noritsugu Umehara, Xiaochun Li

Tribology International 152 巻頁： 106565 2020年8月

The wear classification of MoDTC-derived particles on silicon and hydrogenated diamond-like carbon at room temperature 査読有り国際誌

Kassim K. A. M., Tokoroyama T., Murashima M., Umehara N.

TRIBOLOGY INTERNATIONAL 147 巻頁： 106176 2020年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Tribology International

Molybdenum dithiocarbamate (MoDTC) is well-known as a friction-modifier in engine oil but has wear accelerating effects on DLC/steel sliding contact. Since MoDTC was reported degradable to other materials, the effect of each material on wear acceleration has not been clarified yet. Therefore, it is necessary to divide which Mo-derived compound has a major role to enhance wear. Thus, powder-type MoDTC, MoO3, Mo2C, MoS2, and Mo were dispersed into Poly-alpha-olefin (PAO), and tested on a-C:H and Si-DLC against steel ball at room temperature. For Mo2C, MoDTC, and MoO3, the specific wear rate of a-C:H was approximately 3.4 × 10−5, 3.2 × 10−6 and 1.5 × 10−6 mm3/Nm, respectively. MoDTC indicated higher affection than MoO3 regardless of the particles’ hardness. Si-DLC showed better wear prevention compared to a-C:H.

DOI： 10.1016/j.triboint.2020.106176

Effect of mesh structure of tetrahedral amorphous carbon (ta-C) coating on friction and wear properties under base-oil lubrication condition 査読有り国際共著国際誌

Bin Mustafa Mohd Muhyiddin, Umehara Noritsugu, Tokoroyama Takayuki, Murashima Motoyuki, Shibata Akinori, Utsumi Yoshiharu, Moriguchi Hideki

TRIBOLOGY INTERNATIONAL 147 巻頁： 105557 2020年7月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Tribology International

This study examined the tribological properties of novel mesh tetrahedral amorphous carbon (Mesh ta-C). Subsequently, comparison was made with conventional ta-C and a-C:H coatings under base-oil lubrication via cylindrical-pin-on-disk tribo-tester. Analysis of wear track was conducted using field-emission-scanning-electron-microscope (FE-SEM), atomic-force-microscopy (AFM), and Raman-spectroscopy. The friction coefficient for Mesh ta-C and conventional ta-C revealed a similar pattern with regard to loads. The Mesh ta-C had excellent wear resistance, where the wear rates at loads of 20 N was five and 20 times lower than conventional a-C:H and ta-C, respectively. High wear resistance of Mesh ta-C characterized by inhibition of brittle micro-fracture propagation, less in abrasive particle created during friction test, and suppressing the effect of graphitization-induced wear on the contact surface.

DOI： 10.1016/j.triboint.2019.01.016

Effect of defects on wear behavior in ta-C coating prepared by filtered cathodic vacuum arc deposition 査読有り国際共著国際誌

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

DIAMOND AND RELATED MATERIALS 105 巻頁： 107789 - 107789 2020年5月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Diamond and Related Materials

This study examined the tribological behavior of a ta-C coating fabricated at a substrate bias of −100 V via filtered cathodic vacuum arc (FCVA) deposition. Defects in the ta-C coating were categorized as droplets, pores, and spikes, considering the morphological, structural, and mechanical properties of the ta-C surface. A friction test was conducted at 170 °C in ambient air using a ball-on-disk tribometer. The friction coefficient was 0.08 during the steady state and the wear rate was 4.3 × 10−6 mm3/Nm. To explain the friction and wear behavior, the morphological and structural properties of the defects in the designated area were compared among different sliding cycles.

DOI： 10.1016/j.diamond.2020.107789

The Surface Enhanced Raman Scattering Analysis for Carbonaceous Coating by Using Au Nano-Particles 査読有り国際誌

T. Takayuki, M. Murashima, N. Umehara

TRIBOLOGY ONLINE 15 巻 ( 5 ) 頁： 300 - 308 2020年5月

シェーバーのトライボロジー

野老山貴行, 梅原徳次

トライボロジスト 65 巻 ( 4 ) 頁： 236 - 241 2020年4月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本トライボロジー学会

From time immemorial, shaving one’s beard has been continued. Using razor or electric shaver is common for all male adult to show their cleanliness recently. The custom for shaving my beard by myself was harbingered by World War I and II. Tremendous safety razors were provided by US government to frontline infantry, then they acquired a custom of “shaving by myself”. An electric shaver was invented early of the 20th century, and it is divided two shaving motion, a rotation or a reciprocation. In this article, investigating the relation between inner blade’s edge radiuses and pulling force, clarifying differences of shaving mechanism of a rotation or a reciprocation type shaver by a high speed camera with measuring pulling force simultaneously are explained.

DOI： 10.18914/tribologist.65.04_236

New droplet removal polishing method for diamond-like carbon with carbon fiber brush 査読有り国際誌

Murashima M., Imaizumi Y., Umehara N., Tokoroyama T.

International Journal of Automation Technology 14 巻 ( 2 ) 頁： 190 - 199 2020年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：富士技術出版株式会社

In this paper, we propose a new polishing method for diamond-like carbon (DLC) coatings using a carbon fiber brush (CFB). Surface finishing is an important process for DLC coating applications. A lapping process is widely used for attaining tetrahedral amorphous carbon (ta-C) coatings, which are a type of DLC coating containing many droplets, to obtain fine flat surfaces. The lapping process removes protuberant parts of droplets rather than the entire droplet. In this paper, we propose a new polish brush material made of carbon fiber, called CFB. Carbon fiber has both mechanical strength due to its hard carbonaceous material and flexibility due to its fiber structure. In polishing tests, CFB removed droplets from ta-C coatings and the removal effect increased with the shortening of the brush length. The surface profiles of the polished surfaces indicated that a shorter brush length yielded deep scratch marks on ta-C surfaces. Consequently, the arithmetic average surface roughness of the polished ta-C surfaces, Sa, had almost the same value as that of a non-polished surface. Here, we show the ability of CFB to remove the droplets without an increase in the surface roughness. The CFB with the longest brush length in the present study (12 mm) showed a ten-point average roughness SZJI S = 75 nm and Sa = 4.7 nm, which were 59% and 22% lower than those of the non-polished surface, respectively. Furthermore, the longest CFB removed the entire droplets whereas a shorter CFB merely removed the protuberant part of the droplets. The result indicates that CFB polishing can remove entire droplets, which result in abrasive wear or deterioration. From other polishing tests, the optimum polishing distance was determined. Shorter polishing distances could not remove droplets sufficiently whereas longer polishing distances caused deep scratches on ta-C surfaces due to the material transferred to the CFB. Accordingly, the polishing distance of 600 m showed the best surface finishing with SZJI N = 25 nm and Ra = 0.43 nm, which were 86% lower than and similar to those of the non-polished ta-C surface, respectively.

DOI： 10.20965/ijat.2020.p0190