Wear Analysis of DLC Coating in Oil Containing Mo-DTC

Shinyoshi, Takatoshi; Fuwa, Yoshio; Ozaki, Yoshinori

doi:10.4271/2007-01-1969

Cited by 37 publications

(38 citation statements)

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“…It is also reported that hydrogenated DLC coatings can exhibit considerably low friction performance under lubricated condition in the presence of MoDTC and ZnDTP additives, since MoS2 tribofilm can be formed effectively [11]. However, it is reported that the wear of DLC coatings increase in the presence of MoDTC in the oil [12]. MoO3 observed on the worn surface increases with an increasing hydrogen content of DLC coatings during DLC/steel sliding contact with MoDTCcontaining oil [10].…”

Section: Introductionmentioning

confidence: 94%

Friction and Wear Properties of Tetrahedral Si-Containing Hydrogenated Diamond-Like Carbon Coating under Lubricated Condition with Engine-Oil Containing ZnDTP and MoDTC

Komori

Umehara

2017

Tribology Online

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In this study, we investigated tribological properties of "tetrahedral" Si-containing hydrogenated DLC coating (TMS coating) during sliding against steel or cast-iron lubricated with engine-oil containing MoDTC and ZnDTP additives. TMS coatings derived from only tetramethylsilane were prepared using PACVD with high-bias process. TMS coating had the highly carbon sp 3 bonded structure induced by Si (over 20 at.%) with high hydrogen content (30 at.%). TOF-SIMS analysis showed that TMS coating could form the additive-derived tribofilm on both of the non-ferrous coating surface and the ferrous counter surface to promote Mo-sulfide formation effectively, leading a low friction coefficient. The tribo-chemical reactions were related not only to Mo-sulfides formation, but also reduction of Mo-oxides. Mo-oxides could react with DLC material and induce hydrogen evolution and transformation into further weak carbon structure, causing an increasing wear of hydrogenated DLCs. TMS coating showed no significant wear in spite of plenty hydrogen content. Si induced sp 3 bond and could act so as not to induce clustering of the sp 2 phase. This could inhibit increasing wear of the DLC in the presence of MoDTC. The effectiveness of TMS coating in friction and wear behavior was shown to depend on tribo-chemical reactions and transformation of carbon bond structure.

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Section: Introductionmentioning

confidence: 94%

Friction and Wear Properties of Tetrahedral Si-Containing Hydrogenated Diamond-Like Carbon Coating under Lubricated Condition with Engine-Oil Containing ZnDTP and MoDTC

Komori

Umehara

2017

Tribology Online

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“…As mentioned earlier, the effect of MoDTC in increasing wear of DLC coatings has been reported in the literature [16,[18][19][20][21][22][23] however, they mainly used single additive solutions rather than more realistic fully formulated oils. Haque et al [16,18,22,23] reported this effect with MoDTC obtained from multiple sources, suggesting that this phenomenon is independent of the MoDTC molecular structure.…”

Section: Effect Of Mo-fm On A-c:15h Coating Wearmentioning

confidence: 99%

“…The nano-indentation study suggested that, depending on the level of Mo-FM in the oil, the mechanical properties of the a-C:15H coatings were modified and that the wear scar became softer than the as-received coating with increasing the Mo-FM level. It could be either due to the reaction of generated MoO 3 on the pin counterpart with the active sites of DLC (C-H bonds and dangling bonds) which could eventually result in brittleness of the coating and thus high wear [19] or the a-C:15H coating might have undergone temperature and/or stressed induced graphitisation [30][31][32]. …”

Section: Effect Of Mo-fm On A-c:15h Coating Wearmentioning

confidence: 99%

“…Recently, the effect of MoDTC in increasing wear of a DLC coating in a DLC/steel contact has been reported [16,[18][19][20][21][22][23]. Haque et al [16] showed that DLCs rubbed against steel in the presence of a MoDTC-containing base oil gave extremely high wear but that the addition of the antiwear additive ZDDP terminated this effect [16].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effect of MoDTC-type friction modifier on the wear performance of a hydrogenated DLC coating

Kosarieh¹,

Morina²,

Lainé³

et al. 2013

Wear

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Abstract:The application of Diamond-Like Carbon (DLC) coatings for automotive components is becoming a promising strategy to cope with the new challenges faced by automotive industries. DLC coatings simultaneously provide low friction and excellent wear resistance which could potentially improve fuel economy and durability of the engine components in contact.The mechanisms by which a non-ferrous material interacts with a variety of lubricant additives is becoming better understood as the research effort in this area increases however there are still significant gaps in the understanding .A better understanding of DLC wear may lead to lubricant additive solutions being tailored for DLC surfaces to provide excellent durability (wear) as well as similar or increased fuel economy (low friction). In this work, the wear and friction properties of DLC coating under boundary lubrication conditions have been investigated.A pin-on-plate tribotester was used to run the experiments using HSS steel plates coated with 15 at.% hydrogenated DLC (a-C:15H) sliding against cast iron pins. One type of fully formulated oil with and without ZDDP and two levels of a MoDTC type friction modifier (Mo-FM) was used in this study. The friction and wear response of the fully formulated oils is discussed in detail.Furthermore, optical and scanning electron microscopes (SEM) were used to observe the wear scar and obtain wear mechanisms. Energy-Dispersive X-ray analysis (EDX) and X-ray Photoelectron Spectroscopy (XPS) analysis were performed on the tribofilms to understand the tribochemical interactions between oil additives and the DLC coating. A nano-indentation study was conducted to observe the changes in the structure of the coating, which can provide a better insight into the wear mode and failure mechanism of such hard coatings.In the light of the physical observations and tribochemical analysis of the wear scar, the wear behaviour of a hydrogenated DLC (a-C:15H) coating was found to depend on the concentration of the MoDTC friction modifier and the wear performance is much better when ZDDP is present in the oil. The tribochemical mechanisms, which contribute to this behaviour, are discussed in this paper.

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“…The current commercially available formulated lubricants are optimized based on ferrous materials. Most recent research has focused on the interactions between current lubricant additives and different types of DLC non-ferrous surfaces [3][4][5][6][7][8][9][10][11]. However, due to there being various types of DLC coatings and the complexity of additives in formulated lubricants, it is important to properly define the DLC coating and the additives in the oil.…”

Section: Introductionmentioning

confidence: 99%

Friction reduction mechanisms in boundary lubricated W-doped DLC coatings

Yang

Neville

Brown³

et al. 2014

Tribology International

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The applications of commercially available Diamond Like Carbon (DLC) coatings have seen a rapid increase whilst a lot of tribochemistry problems are not fully understood. This study looks into a tungsten doped hydrogenated DLC coating reciprocating against cast iron in model oils. Friction and wear of such system are then compared with steel. Raman spectroscopy is used extensively to understand the coating interactions with the lubricant/additives. Our results have demonstrated the way to characterize carbon coating structure in lubrication. It clarified the chemical decomposition of MoDTC to MoS 2 is the dominant process rather than the possible formation of WS 2 in such system. It also enbles application of in-situ tribochemical aspects using Raman spectroscopy in ambient conditions.

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Wear Analysis of DLC Coating in Oil Containing Mo-DTC

Cited by 37 publications

References 0 publications

Friction and Wear Properties of Tetrahedral Si-Containing Hydrogenated Diamond-Like Carbon Coating under Lubricated Condition with Engine-Oil Containing ZnDTP and MoDTC

Friction and Wear Properties of Tetrahedral Si-Containing Hydrogenated Diamond-Like Carbon Coating under Lubricated Condition with Engine-Oil Containing ZnDTP and MoDTC

The effect of MoDTC-type friction modifier on the wear performance of a hydrogenated DLC coating

Friction reduction mechanisms in boundary lubricated W-doped DLC coatings

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