著者

小池 亮 鈴木 厚 栗原 和枝 足立 幸志

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.64, no.8, pp.504-512, 2019-08-15 (Released:2019-08-15)

参考文献数

21

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The viscosity of motor oil gets lower in order to decrease resistance at region of the fluid lubrication. On the other hands, this causes increasing of friction at the boundary lubrication region. For this reason, it is required to use a friction modifier to reduce the boundary friction. MoDTC is especially used as friction modifier. Although the decomposition mechanism of MoDTC has been presumed, it is considered only in the case of metal, not hard coatings. So, it is required to understand the effects of hard coatings to friction in motor oils. We tried to clarify the surface and tribo-film changes depending on the kinds of hard coatings by SEM-EDX, TEM and so on. As a result of experiment of hard coatings against metal, we clarified the process as follows when friction of CrN reduces. In the early stage of friction, Fe of the opposite metal transfers to CrN. Mo2S2O2 intermediate product which is formed by MoDTC decomposition is formed on CrN divided into Fe oxide and Mo sulfide. At this time, crystal orientation between Fe oxide and CrN is matching because the lattice constant of Fe oxide is twice that of CrN. These results show that the crystal structure of hard coatings is important for formation of stable interface. And this newly knowledge is necessary to achieve low friction for systems using hard coatings.

著者

岡 昌男 上村 訓右 足立 幸志

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.17-00036-17-00036, 2017 (Released:2017-06-25)

参考文献数

13

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Necessary conditions for usage of DLC coated mechanical seals were investigated by using ring on ring type sliding tests under various contact pressures and sliding speeds in dry and wet nitrogen. The wear mode of DLC coated SiC mechanical seal can be classified into two types by surface morphology of wear surface called ModeI with smooth surface that is useful as a seal and ModeII with relatively rough surface. The transition condition from ModeI to II is given by a critical μ2PV value, and show 0.025 under dry nitrogen and 0.070 under wet nitrogen. With the increase in PV value, arithmetic average roughness Ra decreases from 0.06 μm to 0.04 μm, and it leads to reduction of friction coefficient from 1.4 to 0.4. On the other hand, structural change of DLC films was not obtained within the condition of Mode I, and the friction was high. ModeI possibly has the desirable condition to DLC films for mechanical seal use. As a conclusion, the operation within critical μ2PV value range which depends on various conditions, and in addition, reduction of the friction coefficient in this range, achieve the increase of operating condition.

著者

足立 幸志 加藤 康司

出版者

公益社団法人 精密工学会

雑誌

精密工学会誌 (ISSN:09120289)

巻号頁・発行日

vol.60, no.10, pp.1410-1415, 1994 (Released:2009-06-30)

参考文献数

43

被引用文献数

1

著者

加藤 康司 野本 和広 野澤 睦雄 足立 幸志

出版者

一般社団法人日本機械学会

雑誌

講演論文集

巻号頁・発行日

vol.2002, no.37, pp.58-59, 2002-03-16