The effect of oil temperature and additive concentration on the wear of non-hydrogenated DLC coating

Tasdemir, Haci Abdullah; Wakayama, Masaharu; Tokoroyama, Takayuki; Kousaka, Hiroyuki; Umehara, Noritsugu; Mabuchi, Yutaka; Higuchi, Tsuyoshi

doi:10.1016/j.triboint.2014.04.015

Cited by 62 publications

(7 citation statements)

References 36 publications

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“…To further enhance the performance of a-C coatings in oil lubricated condition, investigations into the synergetic lubrication between a-Cs and lubricating oils or additives have been extensively conducted for the past decades. However, it was found that most of the successful oil additives (such as ZDDP and MoDTC) that were tailored for metallic surface were less effective for a-Cs due to low reactivity of a-C with those chemically based additives [4,5,6,7,8,9,10]. …”

Section: Introductionmentioning

confidence: 99%

Improved Tribological Performance of Amorphous Carbon (a-C) Coating by ZrO2 Nanoparticles

et al. 2016

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Nanomaterials, such as Graphene, h-BN nanoparticles and MoS2 nanotubes, have shown their ability in improving the tribological performance of amorphous carbon (a-C) coatings. In the current study, the effectiveness of ZrO2 nanoparticles (ZrO2-NPs) in lubricating the self-mated nonhydrogenated a-C contacts was investigated in boundary lubrication regime. The results showed that 13% less friction and 50% less wear compared to the base oil were achieved by employing ZrO2-NPs in the base oil in self-mated a-C contacts. Via analyzing the ZrO2-NPs and the worn a-C surface after tests, it was found that the improved lubrication by ZrO2-NPs was based on “polishing effects”, which is a new phenomenon observed between a-C and nanoparticles. Under the “polishing effect”, micro-plateaus with extremely smooth surface and uniform height were produced on the analyzed a-C surface. The resulting topography of the a-C coating is suitable for ZrO2-NPs to act as nano-bearings between rubbing surfaces. Especially, the ZrO2-NPs exhibited excellent mechanical and chemical stability, even under the severe service condition, suggesting that the combination of nonhydrogenated a-C coating with ZrO2-NPs is an effective, long lasting and environment-friendly lubrication solution.

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Section: Introductionmentioning

confidence: 99%

Improved Tribological Performance of Amorphous Carbon (a-C) Coating by ZrO2 Nanoparticles

et al. 2016

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“…A thickness t and optical properties including refractive index n and extinction coe cient k of the tribo lm was calculated by using a formula of optical interference indicated in Eq. ( 4)- (10). The analysis and consideration was conducted to the tribo lm formed on the ta-C:Ta 0.024 , ta-C:Ta 0.103 , GNC pure, GNC:Ta 0.030 and GNC:Ta 0.113 coatings with every 60 cycles.…”

Section: Transition Of Tribo Lm Thicknessmentioning

confidence: 99%

“…DLC coatings possess an amorphous structure that includes sp 2 and sp 3 bonding of carbon atoms. Consequently, DLC coatings exhibit ideal tribological properties such as low friction, high hardness, and high wear resistance in a dry condition [2][3][4][5] and in presence of lubricant [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Carbon Structure of DLC Coatings on Friction Characteristics of MoDTC-derived Tribofilm by Using an in situ reflectance spectroscopy

Hashizume,

Yamamoto,

Chen

et al. 2023

Preprint

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In this paper, we prepared 6 types of DLC coatings with varying carbon structures (amorphous ta-C coating and GNC coatings that include nano graphite crystals) and different doped Ta amounts to study friction characteristics. Results from the friction test with MoDTC-added lubricant revealed that DLC coatings with a higher ID/IG ratio exhibited a lower friction coefficient. Furthermore, in situ observations using a reflectance spectroscopy showed that the tribofilm formed on the DLC coatings with a higher ID/IG ratio maintained a higher MoS2 / (MoS2 + MoO3) ratio. This ratio strongly correlated with its friction coefficient. From the measurement of a work function of each DLC coating, the DLC coatings with a higher ID/IG ratio had a higher work function, which indicated to include larger amount of the defect of graphite structure. This active defect of graphite structure was considered to enhance the friction reduction effect of MoDTC. The findings of this paper suggest a material design concept for a DLC coating that amplifies the effects of lubricant additives in reducing friction.

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“…Losses due to friction and associated wear can be reduced to an appreciable extent by applying surface-protective coatings and surface treatments on interacting machine parts and components [ 1 , 2 , 3 , 4 ]. Diamond-like carbon (DLC) coatings have been developed as a prominent surface-protective solution for widespread applications because of their outstanding mechanical, friction, wear, and chemical properties [ 5 , 6 , 7 , 8 , 9 ]. DLC coatings are known to be chemically inert [ 10 , 11 ], and the doping of DLC coatings with metals such as tungsten can not only enhance their surface energies but can also increase their ability to interact with lubricants to develop surface-protective films.…”

Section: Introductionmentioning

confidence: 99%

Friction and Wear Performance Evaluation of Bio-Lubricants and DLC Coatings on Cam/Tappet Interface of Internal Combustion Engines

et al. 2021

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The environmental concerns associated with artificially formulated engine oils have forced a shift towards bio-based lubricants. The deposition of hard coatings on engine components and migrating to environmentally friendly green lubricants can help in this regard. Chemically modified forms of vegetable oils, with better low-temperature characteristics and enhanced thermo-oxidative stability, are suitable substitutes to conventional lubricant base oils. The research presented in this manuscript was undertaken to experimentally investigate the wear and friction performance of a possible future generation of an environmentally friendly bio-based lubricant as a potential replacement for conventional engine lubricants. In order to quantify the tribological benefits which can be gained by the deposition of DLC coatings, (an (a-C:H) hydrogenated DLC coating and an (a-C:H:W) tungsten-doped DLC coating) were applied on the cam/tappet interface of a direct acting valve train assembly of an internal combustion engine. The tribological correlation between DLC-coated engine components, lubricant base oils and lubricant additives have been thoroughly investigated in this study using actual engine operating conditions. Two additive-free base oils (polyalphaolefines (PAO) and chemically-modified palm oil (TMP)) and two multi-additive-containing lubricants were used in this investigation. Real-time drive torque was measured to determine the friction force, detailed post-test analysis was performed, which involved the use of a specialized jig to measure camlobe wear. An optical profilometer was used to measure the wear on the tappet, high-resolution scanning electron microscopy was employed to study the wear mechanism and energy-dispersive X-ray spectroscopy was performed on the tested samples to qualitatively access the degradation of the coating. When using additive-free TMP, a low friction coefficient was observed for the cam/tappet interface. The presence of additives further improved the friction characteristics of TMP, resulting in reduced average friction torque values. A tremendous enhancement in wear performance was recorded with a-C:H-coated parts and the coating was able to withstand the test conditions with little or no delamination.

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The effect of oil temperature and additive concentration on the wear of non-hydrogenated DLC coating

Cited by 62 publications

References 36 publications

Improved Tribological Performance of Amorphous Carbon (a-C) Coating by ZrO2 Nanoparticles

Improved Tribological Performance of Amorphous Carbon (a-C) Coating by ZrO2 Nanoparticles

The Effect of Carbon Structure of DLC Coatings on Friction Characteristics of MoDTC-derived Tribofilm by Using an in situ reflectance spectroscopy

Friction and Wear Performance Evaluation of Bio-Lubricants and DLC Coatings on Cam/Tappet Interface of Internal Combustion Engines

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