著者

小野寺 康 佐藤 優子 佐藤 魁星 渡部 誠也 佐々木 信也

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

pp.20-00011, (Released:2020-12-02)

参考文献数

21

---

Friction reduction by engine oil under low temperature as well as high temperature conditions are required because of the increasing number of hybrid vehicles where bulk oil temperature is low. Friction modifier (FM) technology to realize it is required. Friction performance of MoDTC, which works well at high temperature, used with adsorption type friction modifiers, which work well at low temperature, was investigated. Low molecular type, glycerol monooleate (GMO) inhibited friction reduction performance of MoDTC while polymer type FM showed little inhibition. Surface analysis indicated that the reaction film by MoDTC was not existed when the GMO was used together while it existed when it is used with polymer FM (PFM). The cause of the difference was studied by their adsorption performance examined by quartz crystal microbalance. GMO showed high adsorption density, while PFM showed low adsorption density compared to that of MoDTC. The result indicated that GMO competitively adsorbed on the surface, inhibiting the reaction film formation by MoDTC while polymer FM does not. The study indicated that use of the polymer FM with MoDTC is one of the solutions of FM design that works under both high and low temperature.

著者

小野寺 康 佐藤 優子 佐藤 魁星 渡部 誠也 佐々木 信也

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.66, no.1, pp.77-85, 2021-01-15 (Released:2021-01-15)

参考文献数

21

---

Friction reduction by engine oil under low temperature as well as high temperature conditions are required because of the increasing number of hybrid vehicles where bulk oil temperature is low. Friction modifier (FM) technology to realize it is required. Friction performance of MoDTC, which works well at high temperature, used with adsorption type friction modifiers, which work well at low temperature, was investigated. Low molecular type, glycerol monooleate (GMO) inhibited friction reduction performance of MoDTC while polymer type FM showed little inhibition. Surface analysis indicated that the reaction film by MoDTC was not existed when the GMO was used together while it existed when it is used with polymer FM (PFM). The cause of the difference was studied by their adsorption performance examined by quartz crystal microbalance. GMO showed high adsorption density, while PFM showed low adsorption density compared to that of MoDTC. The result indicated that GMO competitively adsorbed on the surface, inhibiting the reaction film formation by MoDTC while polymer FM does not. The study indicated that use of the polymer FM with MoDTC is one of the solutions of FM design that works under both high and low temperature.

著者

渡邉 保奈美 小野寺 康 佐藤 魁星 川田 将平 佐々木 信也

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.67, no.3, pp.191-200, 2022-03-15 (Released:2022-03-15)

参考文献数

20

---

Ionic liquids containing halogens have good lubricity, however, they are reported to cause corrosive wear. In contrast, halogen-free ionic liquids do not cause such corrosive wear, but they do not have good lubricity comparable to the halogen-containing counterparts. In this study, we focused on specific halogen-free boron-containing ionic liquids that exhibited low friction performance. The performance was mainly due to its boron-containing anions, because it was realized with both phosphonium-based and ammonium-based cations. Surface analysis and scratch test with atomic force microscope (AFM) were conducted with phosphonium-based cations to clarify the low friction mechanism. The boron-containing ionic liquid, [BOB][P66614], showed lower friction of around 0.01, which was much lower than MoDTC-containing engine oils did. The cause of the ultra-low friction with [BOB] [P66614] is thought to be due to the fact that the reaction film formed by friction has a very smooth surface and suppresses contact between metals. On the other hand, another boron-containing ionic liquid [BMB] [P66614], which did not form a smooth surface, showed relatively high friction compared to [BOB] [P66614]. Scratch tests with AFM indicated that the softer reaction film derived from [BOB] [P66614] led to the formation of a smooth sliding surface.

著者

渡邉 保奈美 小野寺 康 佐藤 魁星 川田 将平 佐々木 信也

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

pp.21-00014, (Released:2022-01-12)

参考文献数

20

---

Ionic liquids containing halogens have good lubricity, however, they are reported to cause corrosive wear. In contrast, halogen-free ionic liquids do not cause such corrosive wear, but they do not have good lubricity comparable to the halogen-containing counterparts. In this study, we focused on specific halogen-free boron-containing ionic liquids that exhibited low friction performance. The performance was mainly due to its boron-containing anions, because it was realized with both phosphonium-based and ammonium-based cations. Surface analysis and scratch test with atomic force microscope (AFM) were conducted with phosphonium-based cations to clarify the low friction mechanism. The boron-containing ionic liquid, [BOB][P66614], showed lower friction of around 0.01, which was much lower than MoDTC-containing engine oils did. The cause of the ultra-low friction with [BOB] [P66614] is thought to be due to the fact that the reaction film formed by friction has a very smooth surface and suppresses contact between metals. On the other hand, another boron-containing ionic liquid [BMB] [P66614], which did not form a smooth surface, showed relatively high friction compared to [BOB] [P66614]. Scratch tests with AFM indicated that the softer reaction film derived from [BOB] [P66614] led to the formation of a smooth sliding surface.

著者

小野寺 康 佐藤 魁星 渡部 誠也 佐々木 信也

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.66, no.5, pp.363-371, 2021-05-15 (Released:2021-05-15)

参考文献数

16

---

Friction reduction by engine oil under low and high temperature conditions is required because of the increasing number of hybrid vehicles where oil temperature is low. Friction modifier (FM) technology to realize it are required. Friction performance of molybdenum dithiocarbamate (MoDTC) used with adsorption type FMs was investigated, which showed different results depending on types of adsorption type FMs: glycerol monooleate (GMO) inhibited friction reduction while polymer FM (PFM) did not. To understand the cause of the difference, the effect of reaction film formation by Zinc dithiophosphate (ZnDTP), which is crucial for the friction reduction by MoDTC, on adsorption type FMs was investigated. GMO inhibited the reaction film formation by ZnDTP, while PFM did not fully, observed with mini-traction machine spacer layer imaging (MTM-SLIM) and EPMA analysis. The cause was studied by their adsorption performance examined by quartz crystal microbalance (QCM). GMO showed higher adsorption density, while PFM showed lower compared to that of ZnDTP. The result indicated that GMO competitively adsorbed on the surface, inhibiting the reaction film formation by ZnDTP while polymer FM did not. Adsorption performance under co-existence of PFM and ZnDTP indicated that ZnDTP is capable to adsorb on the surface under the existence of PFM. The study indicated that the key to achieve low friction is to use PFM which does not fully inhibit ZnDTP reaction film formation.