A Failure Criterion of Friction Pair under Boundary Lubrication

2012 ◽  
Vol 201-202 ◽  
pp. 213-217
Author(s):  
Yu Tao Yan ◽  
Mai Yang ◽  
Zhi Li Sun ◽  
Li Fang Liu
Keyword(s):  
Chemical Reaction ◽  
Boundary Lubrication ◽  
Failure Criterion ◽  
Friction Pair ◽  
Failure Model ◽  
Adsorption Film ◽  
Base Oil ◽  
Lubricating Film ◽  
Temperature Operating ◽  
Melting Point Eutectic

The formation and lubrication mechanism of boundary lubricating film were discussed. The boundary lubricating film includes adsorption film and chemical reaction film, and has respective temperature operating range. The adsorption film adsorbed in metal surface by Van-der Wads, and the parenchyma is the external friction between adsorption molecule layers. The chemical reaction film is made by the reaction between metal and extreme pressure additive in base oil, and the anti-wear capability is realized by the low-melting point eutectic alloy. The temperature is regarded as a judge criterion for failure of boundary lubrication. The failure model for boundary lubricating film is established. According to the failure model, the failure criterion proposed is effective by analysis of the spiral bevel gear using the finite element method. These results provide a basis for the application of boundary lubrication.

Tribological Properties of Zirconium Oxide, Spinel and Mullite Nanopowders as Lubricating Oil Additives

2016 ◽  
Vol 721 ◽  
pp. 451-455
Author(s):  
Armands Leitans ◽  
Eriks Palcevskis
Keyword(s):  
Tribological Properties ◽  
Zirconium Oxide ◽  
Friction Pair ◽  
Synthesis Method ◽  
Lubricating Oil ◽  
Nanosized Powders ◽  
Base Oil ◽  
Oil Additives ◽  
Oxide Spinel ◽  
Lubricating Oil Additives

In work investigated effects of zirconium oxide (ZrO2), spinel (MgAl2O4) and mullite (Al6Si2O13) nanosized powders on the base oil tribological properties. The nanosized (30-40nm) powders manufactured by plasma chemical synthesis method. Tribological experiments used on ball-on-disc type tribometer, measured coefficient of friction and determined metalic disc wear. Base oil used selectively purified mineral oil (conform SAE-20 viscosity) without any functional additives. Nanosized powders dispersed in base oil at 0.5; 1.0; 2.0; wt.%. At work cocluded, that the adition nanoparticles in base oil, possible reduced friction pair wear and friction coefficient. As the main results include spinel (MgAl2O4) nanoparticles 0.5 and 1.0 wt. % concentration ability reduced friction coeffiecient value.

Synergistic Antiwear Effects of Zinc Dialkyl Dithiophosphate and Different Detergents

2008 ◽  
Author(s):  
G. Pennecot ◽  
K. Komvopoulos ◽  
E. S. Yamaguchi
Keyword(s):  
Wear Rate ◽  
Boundary Lubrication ◽  
Base Oil ◽  
Temperature Range ◽  
Zinc Dialkyl Dithiophosphate ◽  
Contact Voltage ◽  
Lubrication Regime ◽  
Steel Surfaces ◽  
Dialkyl Dithiophosphate ◽  
Insight Into

The effectiveness of blends consisting of base oil, some secondary zinc dialkyl dithiophosphate (ZDDP), and different detergents to form antiwear tribofilms on steel surfaces sliding in the boundary lubrication regime was investigated in the temperature range of 105–125°C. The efficacy of the tribofilms formed from these blends was evaluated in terms of contact voltage and wear rate measurements. The best antiwear performance was demonstrated by the tribofilm formed from the blend containing sulphonate detergent. The results of this study provide insight into competing effects between ZDDP and different detergents that affect significantly the antiwear performance of the formed tribofilms.

scholarly journals Effect of Base Oil Type in Grease Composition on the Lubricating Film Formation in EHD Contacts

Lubricants ◽  
2018 ◽  
Vol 6 (2) ◽  
pp. 32 ◽  
Author(s):  
Dennis Fischer ◽  
Georg Jacobs ◽  
Andreas Stratmann ◽  
Gero Burghardt
Keyword(s):  
Film Formation ◽  
Base Oil ◽  
Lubricating Film ◽  
Grease Composition ◽  
Oil Type

Applicability of an Oil Based Calculation Approach for Wear Risk and Wear Lifetime to Grease Lubricated Gear Pairings

2019 ◽  
Author(s):  
Benedikt J. Siewerin ◽  
Andreas Dobler ◽  
Thomas Tobie ◽  
Karsten Stahl
Keyword(s):  
Film Thickness ◽  
Failure Modes ◽  
Surface Hardness ◽  
Wear Intensity ◽  
Experimental Investigations ◽  
Limiting Factor ◽  
Slow Speed ◽  
Base Oil ◽  
Wear Rates ◽  
Lubricating Film

Abstract Gear pairings often run under very high loads. That can result in different kinds of failure modes limiting their lifetime. Many of the known gear failure modes are tribologically influenced. Especially for gear pairs running with lower circumferential speeds or with different surface hardness, (continuous or slow speed) wear is often the lifetime limiting factor. Slow speed wear appears continuously over a longer period of runtime. In many cases, such applications are lubricated with greases. Since the standardized calculation methods (e.g. ISO 6336) do not cover any determination of wear, one common way to predict the wear lifetime is the calculation method according to Plewe. In the associated Plewe diagram the worn off amount of material is correlated to the minimal lubricant film thickness in the tooth contact. The wear intensity decreases for higher film thicknesses. However, this method has certain limits for greases, because the film thickness of a grease, its bleed oil and the base oil is not necessarily the same. Additionally, the consistency and the flow properties have to be considered, because they influence the lubrication supply mechanism (circulating or channeling). Under certain circumstances channeling could be predominant. Although in theory a grease should build a thicker lubricating film than its base oil, experimental investigations have shown higher wear rates in comparison to oil lubrication.

A Boundary Lubrication Friction Model Sensitive to Detailed Engine Oil Formulation in an Automotive Cam/Follower Interface

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Rupesh Roshan ◽  
Martin Priest ◽  
Anne Neville ◽  
Ardian Morina ◽  
Xin Xia ◽  
...  
Keyword(s):  
Boundary Lubrication ◽  
Fuel Efficiency ◽  
Lubricant Additive ◽  
Friction Model ◽  
Operating Conditions ◽  
Valve Train ◽  
Engine Oil ◽  
Contact Friction ◽  
Boundary Lubrication Friction ◽  
Base Oil

Theoretical studies have shown that in severe operating conditions, valve train friction losses are significant and have an adverse effect on fuel efficiency. However, recent studies have shown that existing valve train friction models do not reliably predict friction in boundary and mixed lubrication conditions and are not sensitive to lubricant chemistry. In these conditions, the friction losses depend on the tribological performance of tribofilms formed as a result of surface–lubricant additive interactions. In this study, key tribological parameters were extracted from a direct acting tappet type Ford Zetec SE (Sigma) valve train, and controlled experiments were performed in a block-on-ring tribometer under conditions representative of boundary lubrication in a cam and follower contact. Friction was recorded for the tribofilms formed by molybdenum dithiocarbamate (MoDTC), zinc dialkyldithiophosphate (ZDDP), detergent (calcium sulfonate), and dispersant (polyisobutylene succinimide) additives in an ester-containing synthetic polyalphaolefin (PAO) base oil on AISI E52100 steel components. A multiple linear regression technique was used to obtain a friction model in boundary lubrication from the friction data taken from the block-on-ring tribometer tests. The model was developed empirically as a function of the ZDDP, MoDTC, detergent, and dispersant concentration in the oil and the temperature and sliding speed. The resulting friction model is sensitive to lubricant chemistry in boundary lubrication. The tribofilm friction model showed sensitivity to the ZDDP–MoDTC, MoDTC–dispersant, MoDTC–speed, ZDDP–temperature, detergent–temperature, and detergent–speed interactions. Friction decreases with an increase in the temperature for all ZDDP/MoDTC ratios, and oils containing detergent and dispersant showed high friction due to antagonistic interactions between MoDTC–detergent and MoDTC–dispersant additive combinations.

The effect of femoral head diameter upon lubrication and wear of metal-on-metal total hip replacements

2001 ◽  
Vol 215 (2) ◽  
pp. 161-170 ◽  
Author(s):  
S L Smith ◽  
D Dowson ◽  
A A J Goldsmith
Keyword(s):  
Wear Rate ◽  
Boundary Lubrication ◽  
Wear Testing ◽  
Wear Rates ◽  
Surface Separation ◽  
Lubricating Film ◽  
Lubrication Regime ◽  
Metal On Metal ◽  
The Mean ◽  
Mixed Lubrication Regime

It has been found that a remarkable reduction in the wear of metal-on-metal hip joints can be achieved by simply increasing the diameter of the joint. A tribological evaluation of metal-on-metal joints of 16, 22,225, 28 and 36 mm diameter was conducted in 25 per cent bovine serum using a hip joint simulator. The joints were subject to dynamic motion and loading cycles simulating walking for both lubrication and wear studies. For each size of joint in the lubrication study, an electrical resistivity technique was used to detect the extent of surface separation through a complete walking cycle. Wear of each size of joint was measured gravimetrically in wear tests of at least 2 × 106 cycles duration. Joints of 16 and 22.225mm diameter showed no surface separation in the lubrication study. This suggested that wear would be proportional to the sliding distance and hence joint size in this boundary lubrication regime. A 28 mm diameter joint showed only limited evidence of surface separation suggesting that these joints were operating in a mixed lubrication regime. A 36 mm diameter joint showed surface separation for considerable parts of each walking cycle and hence evidence of the formation of a protective lubricating film. Wear testing of 16 and 22.225mm diameter metal-on-metal joints gave mean wear rates of 4.85 and 6.30mm3/106 cycles respectively. The ratio of these wear rates, 0.77, is approximately the same as the joint diameters ratio, 16/22.225 or 0.72, as expected from simple wear theory for dry or boundary lubrication conditions. No bedding-in was observed with these smaller diameter joints. For the 28 mm diameter joint, from 0 to 2 × 106 cycles, the mean wear rate was 1.62 mm3/106 cycles as the joints bedded-in. Following bedding-in, from 2.0 × 106 to 4.7 × 106 cycles, the wear rate was 0.54mm3/106 cycles. As reported previously by Goldsmith in 2000 [1], the mean steady state wear rate of the 36 mm diameter joints was lower than those of all the other diameters at 0.07 mm3/106 cycles. For a range of joints of various diameters, subjected to identical test conditions, mean wear rates differed by almost two orders of magnitude. This study has demonstrated that the application of sound tribological principles to prosthetic design can reduce the wear of metal-on-metal joints, using currently available materials, to a negligible level.

scholarly journals Boundary lubrication by adsorption film

Friction ◽  
2015 ◽  
Vol 3 (2) ◽  
pp. 115-147 ◽  
Author(s):  
Jun Zhang ◽  
Yonggang Meng
Keyword(s):  
Boundary Lubrication ◽  
Adsorption Film

Hardness effect of DLC on tribological properties for sliding bearing under boundary lubrication condition in additive-free mineral base oil

2013 ◽  
Vol 65 ◽  
pp. 265-269 ◽  
Author(s):  
Nor Azmmi Bin Masripan ◽  
Kenji Ohara ◽  
Noritsugu Umehara ◽  
Hiroyuki Kousaka ◽  
Takayuki Tokoroyama ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Boundary Lubrication ◽  
Sliding Bearing ◽  
Base Oil ◽  
Lubrication Condition ◽  
Mineral Base

Tribological behaviour of graphene oxide sheets as lubricating additives in bio-oil

2018 ◽  
Vol 70 (8) ◽  
pp. 1396-1401 ◽  
Author(s):  
Daoyi Wu ◽  
Yufu Xu ◽  
Lulu Yao ◽  
Tao You ◽  
Xianguo Hu
Keyword(s):  
Graphene Oxide ◽  
Friction Coefficient ◽  
Wear Loss ◽  
Tribological Behaviour ◽  
Low Friction ◽  
Content Type ◽  
Base Oil ◽  
Lubricating Film ◽  
Bio Oil ◽  
Practical Implications

Purpose This paper aims to study the upgradation of the lubricating performance of the renewable base oil , and to study the tribological behavior of graphene oxide (GO) sheets used as lubricating additives in bio-oil for iron/steel contact. Design/methodology/approach A multifunctional end-face tribometer was used to characterize the friction coefficient and wear loss of the tribosystem under different lubricants. Findings The experimental results show that GO sheets with small size benefit lubricating effects and the optimal concentration of GO sheets in bio-oil is 0.4-0.6 per cent, which can form a complete lubricating film on the frictional interfaces and obtain a low friction coefficient and wear loss. Higher concentration of GO sheets can result in a significant aggregation of the sheets, reducing the content of the lubricating components in the bio-oil, which results in the increase in friction and wear; at this stage, the main wear pattern was ascribed to adhesive wear. Practical implications These results show a promising prospect of improving the tribological performance of renewable base oil with the introduction of GO sheets as additives. Originality/value No literature has covered the tribological behaviour of GO sheets in bio-oil. This study contributes to accelerating the application of bio-oil.

scholarly journals Tribological Performance of Nanocomposite Carbon Lubricant Additive

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 149 ◽  
Author(s):  
Chuanyi Xue ◽  
Shouren Wang ◽  
Daosheng Wen ◽  
Gaoqi Wang ◽  
Yong Wang
Keyword(s):  
Friction And Wear ◽  
Frictional Contact ◽  
Adhesive Wear ◽  
Friction Pair ◽  
Lubricant Additive ◽  
Suspension Stability ◽  
Wear Performance ◽  
Base Oil ◽  
Test Conditions ◽  
Friction And Wear Characteristics

In this research, nanocomposite carbon has been found to have excellent tribological properties as a lubricant additive. To reduce high friction and wear in friction pairs, the modified nanocomposite carbon has been prepared for chemical technology. The morphology and microstructure of the modified nanocomposite carbon were investigated via TEM, SEM, EDS, XPS, and Raman. In this study, varying concentrations (1, 3, and 5 wt. %) within the modified nanocomposite carbon were dispersed at 350 SN lubricant for base oil. The suspension stability of lubricating oils with the modified nanocomposite carbon was determined by ultraviolet-visible light (UV-VIS) spectrophotometry. The friction and wear characteristics of lubricants containing materials of the modified nanocomposite carbon were evaluated under reciprocating test conditions to simulate contact. The morphology and microstructure of the friction pair tribofilms produced during frictional contact were investigated via SEM, EDS, and a 3D surface profiler. The results showed that scratches, pits, grooves, and adhesive wear were significantly reduced on the surface of the friction pair which was used with 3% nanocomposite carbon lubricant. Additionally, the modified nanocomposite carbon showed excellent friction reducing and anti-wear performance, with great potential for the application of anti-wear.

Sign in / Sign up

Export Citation Format

Share Document