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In this study, a comprehensive regeneration process was employed to enhance the recycling efficiency and performance of waste gear oil. The process began with the waste gear oil subjected to extraction flocculation, which was then followed by vacuum distillation for solvent removal. Then, catalytic hydrogenation was performed, and HiTEC 3339 additive was incorporated at concentrations that ranged from 0.25% to 1.5%, thus resulting in the regenerated gear oil. The tribological properties of the regenerated gear oil were investigated under various load conditions using a friction and wear testing apparatus. When a load of 10 N was applied, the filtered oil (Oil 2) exhibited an average friction coefficient of 0.092 and a volumetric wear rate of 8.25 × 10−8 mm3/Nm, which represented reductions of 8.23% and 42.7%, respectively, when compared to the unfiltered oil (Oil 1). As the load was increased to 50 N, Oil 2 demonstrated a wear rate of 23.4 × 10−8 mm3/Nm, indicating a 20.9% improvement in wear resistance. As the concentration of the additive increased, the following trends were observed: (i) Under a load of 10 N, the friction coefficients demonstrated a gradual decreasing trend, while at 50 N, the friction coefficients were remarkably similar and significantly lower than those at 10 N. (ii) The wear rates initially decreased and then increased. Among the tested lubricants, Oil 4 (containing 0.5% HiTEC 3339) exhibited the shallowest wear scar depth under various loads, which indicated superior anti-wear performance. When Oil 4 was thoroughly evaluated through bench tests, it indicated excellent extreme pressure and anti-wear properties, as well as superior rust and corrosion prevention capabilities and high–low temperature performance. The overall performance indicators of Oil 4 were discovered to be similar to those of fresh oil. [ABSTRACT FROM AUTHOR]

With the aim of improving the tribological properties of low-viscosity gear oil for automobiles, an acrylate of dialkyl dithiophosphoric acid (ADDP) with strong polar groups was synthesized. The tribological behavior of ADDP combined with molybdenum dialkyl dithiocarbamate (MoDTC) in gear oil was systematically studied. Tribological performances of gear oil containing different additives were assessed using a four-ball friction and wear tester. The obtained tribological characteristics reveal that ADDP and MoDTC can significantly improve the antiwear and antifriction performance of low-viscosity gear oil. Moreover, compared with using MoDTC or ADDP alone, the average friction coefficient and wear scar diameter of ADDP combined with MoDTC further decreased by 2.41–19.15% and 5.00–18.19%, respectively. Analysis of the worn surface showed that the structural characteristics and physical synergistic lubricating actions of the ADDP with MoDTC additives during the friction process can contribute to the exceptional tribological properties of the hybrid additives. [ABSTRACT FROM AUTHOR]

AbstractThe practice of employing efficient lubricants involving functional additives has become imperative in order to enhance engine efficiency, to say the least. The span of an engine’s life can be greatly enhanced by gear oil’s tribological and thermo-physical properties. Addressing the tribological management of gearbox components within the mechanical sector is a dire necessity. In a quest for exceptional nanolubricants with improved serviceability, present manuscript deals with the dispersion of metallic-sulphide nano dispersants in gear oil lubricant. Nanolubricants were prepared by dispersing molybdenum disulfide nanoparticles (MoS2 Nps) in gear oil with varying concentrations of 0.1%, 0.3%, and 0.5% by volume (v/v). Then nanolubricants’ thermo-physical properties were assessed and contrasted with those of plain gear oil. This was followed by the measurement of the tribological and extreme pressure properties of the nanolubricant samples on a four-ball tester. According to the findings, as compared to gear oil, the prepared nanolubricant yielded a maximum reduction of 9.21% and 9.38% in coefficient of friction and an average wear scar diameter, respectively. A maximum augmentation of 12% in weld load was obtained with 0.3% nanolubricant sample. The wear scar on the steel balls was examined using field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscope (EDS). The investigations revealed the presence of ball bearing and surface polishing effects as dominant lubricating mechanisms, which potentially contribute to the enhanced tribological properties of the oil. Hence, adding MoS2 Nps in gear oil may solve many engineering problems related to the lubricity of the base oil. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this paper is to study the parameters that affect the remaining useful life of lubricant (RULL). Fourier‐transform infrared spectroscopy (FTIR) of gear oil is used to observe the contamination in the oil. Coefficient of friction (COF) has been found out using pin on disc tribometer using gear oil, and simultaneously, wear debris has been collected. Particles distribution and elemental analysis of wear debris were observed by emission scanning electron microscopy (FESEM) Field with energy dispersive x‐ray (EDX) respectively. Oxidation, sulfation, soot and water content in lubricant increase with time and decrease the RULL. ANOVA is applied to find out the most influential parameter for wear debris and found a load on gears is the dominating factor for wear. This method is the potential to monitor the root causes of contamination and change in lubricant properties and may help to detect the other early signs of failure. [ABSTRACT FROM AUTHOR]

The results of thermal studies of some derivatives of dithiophosphoric, xanthogenic, dithiocarbamic acids are presented. The thermal parameters of the compounds were determined both in pure form and in the presence of iron and copper powders. Their chemical activity with respect to iron and copper was studied. It has been found that the temperature at which the thermal stability of the studied compounds is maintained exceeds 1700С, and they are chemically active with respect to iron and copper: the lower the interaction temperature within the same row with iron and copper and the lower its mass loss corresponding to this temperature, the more effective it is like an extreme pressure (EP) additive. It has been found that compounds of the same series, reacting with metal by the type of synchronous and exchange reactions, have better indicators of extreme pressure properties than compounds interacting with metal by the type of asynchronous reaction. [ABSTRACT FROM AUTHOR]

With the aim of improving the tribological properties of low-viscosity gear oil for automobiles, an acrylate of dialkyl dithiophosphoric acid (ADDP) with strong polar groups was synthesized. The tribological behavior of ADDP combined with molybdenum dialkyl dithiocarbamate (MoDTC) in gear oil was systematically studied. Tribological performances of gear oil containing different additives were assessed using a four-ball friction and wear tester. The obtained tribological characteristics reveal that ADDP and MoDTC can significantly improve the antiwear and antifriction performance of low-viscosity gear oil. Moreover, compared with using MoDTC or ADDP alone, the average friction coefficient and wear scar diameter of ADDP combined with MoDTC further decreased by 2.41–19.15% and 5.00–18.19%, respectively. Analysis of the worn surface showed that the structural characteristics and physical synergistic lubricating actions of the ADDP with MoDTC additives during the friction process can contribute to the exceptional tribological properties of the hybrid additives.

In order to realize the localization of unmanned helicopter gear oil，the influence of different performance gear oil on gearbox performance is clarified，so as to improve the reliability and service life of gearbox scientifically. Zhengzhou Research Institute of Mechanical Engineering Co.， Ltd.， jointly developed 80W-140 unmanned helicopter gear oil. Based on the performance test of the oil in the laboratory，the performance of the 80W-140 unmanned gear oil is compared and tested with that of the imported oil through the gearbox comprehensive test bench. The vibration，noise，temperature，efficiency and gluing torque obtained from the bench test are carried out，the results show that different performance oils have obvious different effects on the efficiency and bearing capacity of the gearbox， the 80W-140 oil product has better friction reduction，anti-wear and anti gluing performance，which can effectively improve the reliability of the gearbox.

The study aim is to develop methods of efficiency enhancement for the antiwear additives in the lubricants based on hydrocarbon oils. The tribological properties of triaryl and trialkyl phosphorothionates with similar hydrocarbyl groups have been compared. The testing has been carried out in the contact unit of combined rolling and sliding friction. It has been shown that trioctyl phosphorothionate is considerably superior to tribenzyl phosphorothionate and triphenyl phosphorothionate in antifriction and antiwear properties. The obtained results validate the suggestion that for a given polar group contained in an antiwear additive molecule the maximal efficiency can be achieved with sufficiently great hydrocarbonyl groups, when their structures are similar to the prevailing structure of the lubricant hydrocarbon molecules. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, the facile synthesis and identification of hexylmethylimidazolium bis(trifluoromethyl­sulfonyl)­amide ([HMIM]­TFSA) and hexylmethylimidazolium triethyltrifluorophosphate ([HMIM]FAP) ionic liquids (ILs), as multifunctional and multipurpose gear oil additives, is introduced. The tribological tests indicated that both ([HMIM]TFSA) and ([HMIM]FAP) ILs demonstrate antiwear/extreme pressure properties (AW/EP) to the gear oils by preventing wear and scar of the lubricated system at low and high temperatures. [HMIM]TFSA provided superior performance in comparison to [HMIM]FAP. Because of the presence of heteroaromatic imidazole moiety in the ILs structure, the prepared ILs also imparted anticorrosion, antioxidant, and anti-rust properties to the lubricant. All these observations confirmed that the ILs are single component multifunctional and multipurpose oil additives. In addition, due to avoiding the use of toxic and harmful elements in the preparation of ILs make the fabricated oils potential candidates for green lubricants.

The quality and reliability of consumables, including gear oils, results in the failure-free operation of the transmission components in heavy trucks. It is known that oil viscosity is essential for all lubricated tribopairs for wear and friction reduction in all vehicles with a gearbox. Viscosity may be influenced by the contamination that wear products can impart on the oil. Oil contamination can also affect lubrication efficiency in the boundary friction conditions in gearboxes where slips occur (including bevel and hypoid gearboxes). The present research focused on this issue. An obvious hypothesis was adopted, where it was theorized that exploiting the contaminants that are present in gear oil may affect how the lubricating properties of gear oils deteriorate. Laboratory tests were performed on contaminants that are commonly found in gear oil using the Parker Laser CM20. The study was designed to identify a number of different solid particles that are present in oil. At the second stage, friction tests were conducted for a friction couple "ball-on-disc" in an oil bath at 90 °C on a CSM microtribometer. The quantitative contamination of the gear oils that contained solid particles and the curves representing the friction coefficients of fresh oils with a history of exploitation were compared. The test results were statistically analysed. Exploitation was shown to have a significant impact on the contamination of gear oils. It was revealed that the contamination and the mileage had no effect on the tested oils. [ABSTRACT FROM AUTHOR]

Copyright of Tribologie und Schmierungstechnik is the property of Narr Francke Attempto Verlag GmbH & Co.KG and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of the Society of Plant Engineers Japan is the property of Society of Plant Engineers Japan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, the facile synthesis and identification of hexylmethylimidazolium bis(trifluoromethyl sulfonyl) amide ([HMIM]TFSA) and hexylmethylimidazolium triethyltrifluorophosphate ([HMIM]FAP) ionic liquids (ILs), as multifunctional and multipurpose gear oil additives, is introduced. The tribological tests indicated that both ([HMIM]TFSA) and ([HMIM]FAP) ILs demonstrate antiwear/extreme pressure properties (AW/EP) to the gear oils by preventing wear and scar of the lubricated system at low and high temperatures. [HMIM]TFSA provided superior performance in comparison to [HMIM] FAP. Because of the presence of heteroaromatic imidazole moiety in the ILs structure, the prepared ILs also imparted anti-corrosion, antioxidant, and anti-rust properties to the lubricant. All these observations confirmed that the ILs are single component multifunctional and multipurpose oil additives. Also, due to avoiding the use of toxic and harmful elements in the preparation of ILs make the fabricated oils potential candidates for green lubricants. [ABSTRACT FROM AUTHOR]

The interaction of transmission oils based on pentaerythritol esters and organosiloxane liquids with a surface of AISI 420S steel was studied. It was found that during friction, the lubricant interacts with the iron of the steel surface, resulting in the formation of protective surface films of sulfur and silicon compounds. The features of formation of protective surface films during friction with lubricants based on pentaerythritol esters and organosiloxane liquids are determined. It is noted that the formation of protective films when using a lubricant composition of pentaerythritol esters occurs with the participation of nonoxidized iron, and when using organosiloxane liquids with the participation of iron oxide, the main element of the metal counterbody. [ABSTRACT FROM AUTHOR]

The quality and reliability of consumables, including gear oils, results in the failure-free operation of the transmission components in heavy trucks. It is known that oil viscosity is essential for all lubricated tribopairs for wear and friction reduction in all vehicles with a gearbox. Viscosity may be influenced by the contamination that wear products can impart on the oil. Oil contamination can also affect lubrication efficiency in the boundary friction conditions in gearboxes where slips occur (including bevel and hypoid gearboxes). The present research focused on this issue. An obvious hypothesis was adopted, where it was theorized that exploiting the contaminants that are present in gear oil may affect how the lubricating properties of gear oils deteriorate. Laboratory tests were performed on contaminants that are commonly found in gear oil using the Parker Laser CM20. The study was designed to identify a number of different solid particles that are present in oil. At the second stage, friction tests were conducted for a friction couple “ball-on-disc” in an oil bath at 90 °C on a CSM microtribometer. The quantitative contamination of the gear oils that contained solid particles and the curves representing the friction coefficients of fresh oils with a history of exploitation were compared. The test results were statistically analysed. Exploitation was shown to have a significant impact on the contamination of gear oils. It was revealed that the contamination and the mileage had no effect on the tested oils.

If bearings for gear units of railway vehicles are damaged by seizing, parts of the bearings come off and damage the gear and the gear box, which may lead to the leakage of the gear oil and the defective rotation of the wheel sets. Tapered roller bearings are mostly used in the gear units in Japan. The sliding speeds at the contact surface between the roller end and the inner ring flange of the pinion bearings are higher than that of the gear bearings. In the pinion bearings, therefore, seizure may occur by metal-to-metal contact from inadequate lubrication between the roller end and the inner ring flange. In order to prevent seizure of the bearings and to improve the reliability of the gear units, it is important to clarify the causes of the inadequate lubrication and the mechanism developing from inadequate lubrication into seizure of the bearings. In this work, the effects of bearing rotational speeds and loads, gear oil temperatures and flow rates, and endplay (internal clearance of bearings) values on the performance of the bearings have been investigated by using a rotation testing apparatus for pinion bearings. As a result, it has been clarified that the heating value from bearings increase as the oil temperature decreases and as the oil flow rate increases. In addition, it has been found that the endplay value is greatly reduced when the rotational speed of the bearing rapidly accelerates to high speed under conditions where the temperature of the gear oil is relatively low.

Abstract Gear oil of heavy mining machineries are designed to provide anti-wear and anti-friction protection under extreme load condition. In present study thermophysical and tribological properties of industrial gear oil with nanoparticles additives (Al 2 O 3 and SiO 2) has been experimentally evaluated. Morphology of dry nanoparticles under FE-SEM shows that both nanoparticles are spherical. DLS test shows the presence of mild-agglomeration of nanoparticles in the dispersion. Density and viscosity of nanolubricants is tested with varying temperature and particle volume fraction. Measured viscosity results for Al 2 O 3 /gear oil nanolubricants follow the existing empirical model and new model has been proposed for SiO 2 /gear oil nanolubricants. Anti-friction and anti-wear properties of nanolubricants are tested on pin-on-disc test apparatus. FE-SEM and energy dispersive spectroscopy (EDS) analysis of wear scar (pin SS-304), evident the occurrence of ball bearing and surface polishing effects, which may be responsible for advanced tribological properties of the oil. Test results reveals that ball bearing have dominating effect in enhancement of tribological performance. Graphical abstract Image 1 Highlights • Enhancing the tribological performance of the gear via Al 2 O 3 and SiO 2 nanoparticles. • Correlation proposed for the viscosity of gear oil nanolubricant. • Pin-on-disc tribotester displayed 25% and 22% improvement in anti-friction property with 0.3% Al 2 O 3 and SiO 2 nanoparticles. • FESEM and EDS analysis of wear scar reveals the dominance of ball bearing effect over surface polishing effect. [ABSTRACT FROM AUTHOR]

Summary: This study aims to develop a complete methodology for assessing flammability hazards of typical fuels (ie, transformer oil, hydraulic oil, gear oil, and lubricating grease) used in a wind turbine nacelle by combining different experimental techniques such as thermogravimetric analysis and cone calorimetry. Pyrolysis properties (onset temperature, temperature of maximum mass loss rate, and mass residue) and reaction‐to‐fire properties (ignition time, heat release rate, mass loss rate, and smoke release rate) were determined and used for a preliminary assessment of thermal stability and flammability hazards. Additional indices, for ignition and thermal behavior (effective heat of combustion, average smoke yield, and smoke point height, heat release capacity, fire hazard parameter, and smoke parameter, were calculated to provide a more advanced assessment of the hazards in a wind turbine. Results show that pyrolysis of transformer oil, lubricating grease, hydraulic oil, and gear oil occur in the range of 150°C to 550°C. Lubricating grease and transformer oil show the higher and lower thermal stabilities with maximum pyrolysis rate temperatures of 471°C and 282°C, respectively. The measured relation between ignition time and radiant heat flux agrees well with Janssens method (a power of 0.55). The aforementioned indices appear to provide a reasonable prediction of performance under real fire conditions according to a full‐scale fire test documented by Declercq and Van Schevensteen. The results of the study indicate that transformer oil is the easiest to ignite while lubricating grease is the most difficult to ignite but also has the highest smoke production rate; that transformer oil has the highest heat release rate while gear oil has the lowest; and that the fire hazard parameter is the highest for transformer oil and the smoke parameter is the highest for lubricating grease. The potential of this type of work to design safer wind turbines under performance‐based approaches is clearly clarified. [ABSTRACT FROM AUTHOR]

Purpose The present work aims to numerically investigate the natural convective heat transfer performance of aluminium oxide (Al2O3)-gear oil nanolubricant used in heavy earth moving machinery (HEMM).Design/methodology/approach Viscosity, density and thermal conductivity of nanolubricants have been experimentally determined. The numerical simulation has been performed by using computational fluid dynamics (CFD) for a cylinder cavity which resembles shape of automatic transmission system of HEMM. The left wall temperature has been maintained at 293 to 313 K, and right wall is at a constant temperature of 283 K. Due to absence of any experimental study on natural convective heat transfer performance of Al2O3-gear oil nanolubricant, initially CFD model has been tested for accuracy by comparing experimental, and CFD results for Al2O3-water nanofluid has been available in open literature.Findings It has been observed that Nusselt number increases with increase in Rayleigh number, but it decreases with increasing particle volume fraction. The gear oil-based nanolubricant is expected to have the better thermal performance in HEMM at higher temperature.Practical implications The numerical analysis will help to predict the thermal performance of nanolubricant. The outcome may help the designers, researchers and manufacturers of HEMM.Originality/value Most of the previous studies have been limited with base fluid as water, ethylene glycol, etc. in the field of nanofluid. CFD study for thermal performance of Al2O3-gear oil nanolubricant is essential before the experimental work. This work is the preliminary stage of application of, nanolubricant for heat transfer. [ABSTRACT FROM AUTHOR]

Generally synthetic gear oils have superior oxidation stability compared to mineral gear oils, although there is a concern that the oil life may depend on the sludge formation during its oxidation process. In the methods of ASTM D2893 or ASTM D5763 which are commonly used as oxidation tests of gear oils, the test duration for degradation is specified 312 hours. Considering the evaluation to select synthetic gear oils, the test duration is too short to find the significant difference since the degradation of synthetic gear oils would be minimal. The authors provide a new method, in which gear oils are oxidized and degraded by modified dry-TOST (dry-Turbine Oil Oxidation Stability Test) method without catalysts, and use the RPVOT (Rotating Pressure Vessel Oxidation Test) residual ratio as the newly introduced degradation index. This study shows the RPVOT residual ratio has a correlation with changes of kinematic viscosity or acid number which are generally used as the degradation index, and also presents that degradation tendency of the gear oils can be classified by the relationship graph between RPVOT residual ratio and sludge quantity.

The impact of driveline lubricants on rolling element bearing fatigue has been an important concern for many years. The recent emphasis on improved drivetrain efficiency has further heightened interest in the impact of lubricants on bearing life. A number of laboratory roller bearing test machines have been used to qualify lubricants for automotive applications. Included in these is the Unisteel Rolling Fatigue Testing Machine. We herein present results from an experimental matrix of driveline additives tested using a Unisteel test procedure. Statistical analysis of the cycles to pitting failure suggests that there was no difference in calculated bearing fatigue life between additive families taken as a group. Failure analysis of the end-of-test bearings suggests that the observed fatigue lives were primarily governed by poor surface finish on a flat test specimen commonly used to increase contact stress in accelerated Unisteel bearing fatigue test procedures.

In this paper, we present an oil condition and wear debris evaluation method for ship thruster gears using T 2 statistics to form control charts from a multi-sensor platform. The proposed method takes into account the different ambient conditions by multiple linear regression on the mean value as substitution from the normal empirical mean value. This regression approach accounts for the bias imposed on the empirical mean value due to different geographical and seasonal differences on the multi-sensor inputs. Data from a gearbox are used to evaluate the length of the run-in period in order to ensure only quasi-stationary data are included in phase I of the T 2 statistics. Data from two thruster gears onboard two different ships are presented and analyzed, and the selection of the phase I data size is discussed. A graphic overview for quick localization of T 2 signaling is also demonstrated using spider plots. Finally, progression and trending of the T 2 statistics are investigated using orthogonal polynomials for a fix-sized data window. [ABSTRACT FROM AUTHOR]

Wear debris is an indicator of the health of machinery, and the availability of accurate methods for characterising debris is important. In this work, a dual filter model for a gear oil system is used in conjunction with operational data to indicate three different system operating states. The quantity of wear particles in gear oil is analysed with respect to system running conditions. It is shown that the model fits the data in terms of startup “particle burst” phenomenon, quasi-stationary conditions during operation, and clean-up filtration when placed out of operation. In order to establish boundary condition for particle burst phenomenon, the release of wear particles from a pleated mesh filter is measured in a test rig and included in the model. The findings show that a dual filter model, with startup phenomenon included, can describe trends in the wear particle flow observed in the gear oil. Using this model it is possible to draw conclusions on the filtration system performance and wear generation in the gears. Limitations of the proposed model are the lack of ability to describe noise and random burst spikes attributed to measurement error distributions. Trending of gear wear particle generation is made possible by model parameter estimation and identification of an unintended lack of filter change. The model may also be used to optimise system and filtration performance, and to enable continuous condition monitoring. [ABSTRACT FROM AUTHOR]

In this study an extreme pressure and anti-corrosion additive package for gear oils has been created. In this context three different organic molecules were synthesized. Methylene-bis (dibutyldithiocarbamate), Sulfured oleic acid and o,o-Dialkyldithio Phosphate. Mass spectrums and Elemental analyses were carried out for these three molecules. For each molecule 4-ball weld points (WP), 4-ball Wear Scar Diameter (WSD), Copper corrosion (CC) and salt spray tests (SS) were carried out. Antioxidant properties of synthesized molecules were determined. According to the test results eight different additive packages were prepared and WP, WSD, CC and SS tests were applied to each package to determine a suitable package content. The highest yield was obtained in the five and six additive package with 250, 300 kg weld point and 0.41, 0.53 mm scar diameter respectively. For all additive packages the extreme pressure and corrosion resistance properties of gear oil increase by increasing the percentage of Methylene-bis (dibutyldithiocarbamate). o,o-Dialkyldithio Phosphate showed the highest antioxidant activity and it has been obtained bets corrosion protection with Sulfured oleic acid. [ABSTRACT FROM AUTHOR]

Suspension of wear particles in gear oil with respect to the diversity of particle size combined with filter mechanisms has been analyzed. Coupling of wear modes from tribology is combined with particle size bins to show how a mathematical model can be expanded to include information gained from sensors that can segment particles into size bins. In order to establish boundary conditions for the model based on real data, a filtration test is included. Finally, the model is fitted to data from a gear in operation and differences between real data and the model are discussed. The findings show that particles less than 14 μm dominate the wear. Hence, it is concluded that abrasion dominate the wear, for the gear in operation, and it is concluded to be in quasi-stationary mode. The distribution of the particles is observed in conjunction with the particle quantity to determine a basis for normal operation. Limitations to the model in lack of fitting to large and frequent signal spikes are suggested to be caused by measurement equipment and/or model constraints. Predicting the transition from quasi-stationary (normal) mode to break-down mode is made possible by particle quantity detection as well as concentration distribution. [ABSTRACT FROM AUTHOR]

ABSTRACT White and natural base oils are assessed as candidates for the formulation of ecological gear oils. They are compared to 'classical' mineral and polyalphaolefins-based oils in scuffing four-ball and gear tests. Four fully formulated gear oils were prepared by blending each base oil with the package of extreme pressure (EP) additives, an anti-foam additive and an anti-oxidant. It is shown that the resistance to scuffing of the white oil is comparable to the classical oils, but the natural (rapeseed) oil reduces resistance to scuffing, because the used EP additives may not be suited to the rapeseed 'matrix' producing adverse effects. Thus, rapeseed-based gear oils can be used only for the lubrication of gears working under moderate load conditions. It is also indicated that, when comparing the mechanisms of tribochemical action of the EP additives in the four-ball tribosystem and meshing teeth, care should be taken, because the conditions in the contact zones are different. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The high-frequency corrosion fatigue behavior of extruded AZ31 magnesium alloy was investigated in different environments: air, gear oil and 3.5% NaCl solution. Compared with that in air, the corrosion fatigue limits were degraded by approximately 3.52% and 58.91%, respectively, and the corrosion fatigue lives were shortened by about 13.43% and 89.36%, respectively. In the same environment, the high-frequency fatigue limits are all higher than those tested at low frequency. The specimen geometrical shape plays a certain factor on stage characteristics of S–N curves. Compared with that of arc transition specimens, the stress sensitivity of line transition specimens is only reflected in a relatively high cycle fatigue life region. Different environments influence the corrosion failure kinetics processes (the crack initiation mechanism), but do not change the fatigue fracture mechanism of the alloy, and the higher loading frequency only accelerate the crack nucleation processes. [ABSTRACT FROM AUTHOR]