Synthetic Ester Oil Research Articles

Study on the Load Carrying Capacity of Sliding Bearing Lubricated by Synthetic Ester Oils

Study on the Load Carrying Capacity of Sliding Bearing Lubricated by Synthetic Ester Oils

Comparative study of the electrostatic charging tendency between synthetic ester and mineral oil

The growing demands for improved fire safety, source material sustainability, environment friendliness, and asset life extension have driven the research and development efforts of synthetic esters, less-flammable fluids. However the relatively limited number of work on these esters and their cost still limit their uses to specific applications. This contribution reports some investigations onto the Electrostatic Charging Tendency (ECT) of a commercially available ester fluid. Comparison is made with mineral oil, as this is a fluid we are familiar with. Fresh (unaged) and aged fluid samples were investigated in a spinning disk system under laboratory controlled conditions. Changes in static electrification were compared to some aging indexes (interfacial tension, turbidity, relative dissolved decay products). This contribution is not only intended to provide a fresh review in this domain of research, but also contains a substantial amount of new material with a view of closing some gaps in the present state of knowledge of oil streaming electrification. The obtained results show that static electrification currents are affected by fluid motion velocity, type of paper, moisture content and the aging byproducts. It was also found that the removal of dissolved oxygen by nitrogen blanketing contributed to the reduction in static electrification.

Green Ester Lubricants Based on Rapeseed Acid and their Lubricity

Several complex esters were synthesized from phthalic anhydride, neopentyl glycol and rapeseed acid. Their rheological properties, biodegradability and tribological properties were measured. It was found that the complex esters have a wide viscosity range of 126~325mm2/s at 40°C with viscosity indices about 127~143, and solidifying points lower than-38°C. The maximum non seizure load of a complex ester with degree of polymerization 1.42 is as high as 735 N, with a wear scar diameter of 0.41mm, superior to mineral oil. The biodegradation rates are higher than 73%, and the thermal stability is good. So these complex esters are a class of green synthetic ester oils with excellent properties.

Investigations on streamers phenomena in mineral, synthetic and natural ester oils under lightning impulse voltage

This paper presents the experimental results of a comparative study of mineral, synthetic and natural ester oils issued from different origins through the analyze of the initiation threshold voltage of streamers, their pattern and their stopping length (final length) L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> as well as the associated current and electrical charge, in a point - plane electrodes arrangement submitted to a standard lightning impulse voltage (1.2/50 μs). It's shown that the streamers are filamentary in the different tested oils whatever the polarity of voltage. The stopping lengths L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> are longer and the conductivity higher when the point is positive than when it's negative. L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> is generally longer in ester oils (natural and synthetic) than in some mineral oils. When the point is negative, L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> can be ten times higher in ester oils than in mineral ones. Different modes of propagation of streamers are also observed; the transition between these modes of propagation depends on the experimental conditions and the molecular structure of liquid. This transition is well pronounced with some mineral oils when the point is negative.

Comparative study of statistical breakdown in mineral, synthetic and natural ester oils under AC voltage

This paper reports on a comparative study of statistical Breakdown Voltage (BDV) in mineral oils, natural esters (vegetable oils) issued from different origins, and one synthetic ester through the measurements of 32 BDV using spherical electrode under AC voltage according to main lines of IEC 60156 specifications. The Normal and Weibull distribution functions are used to analyze and estimate the BDV probability of these oils. The hypothesis testing is then used to select the distribution functions suitability. We mainly analyze the histogram, frequency, mean, standard deviation and estimate the BDV probability of the sample population. The considered liquids are three different mineral oils (MO3', MO4' and MO5), one synthetic ester (SE1) and three different natural esters (VO2, VO3 and VO4). It's shown that the measured BDV data follow better Normal than Weibull distribution. Basing on the BDV at the levels of risk 1%, 10% and 50% probability for U1%, U10% and U50%, the dielectric withstand of ester oils, under AC, homogeneous field and small gap, is slightly better compared to mineral oils. PCA (Principal Component Analysis) method is also used to analyse the BDV variance of tested oils.

Short alkyl chain imidazolium ionic liquid additives in lubrication of three aluminium alloys with synthetic ester oil

In this study the authors have compared the tribological behaviour of three aluminium alloys (ASTM 2011 T3, ASTM 6061 T6 and ASTM 7075 T6) lubricated with two room temperature ionic liquids (ILs) with the same short alkyl chain imidazolium cation, 1-ethyl-3-methylimidazolium, and two different anions, tetrafluoroborate (BF4) (L102) and bis(trifluoromethylsulfonyl)imide {[(CF3SO2)2N]; NTf} (LNTf102). The ILs were used as 1 wt-% additives of the synthetic ester base oil propylene glycol dioleate (PGDO) in reciprocating sliding tests. The results are discussed in terms of the properties of the lubricants and the hardness of the aluminium alloys. Plastic deformation, wear mechanisms and surface interactions have been studied by electron microscopy (SEM), energy dispersive (EDS) spectroscopy and three-dimensional profilometry. The tribological performance of both ionic liquids is similar, and depends on hardness values and on the degree of plastic deformation of each alloy. Reductions of more than 40% in the wear rate and surface roughness with respect to the base oil are achieved for both additives only for the hardest alloy Al7075. The performance of the additives is independent of the contribution of the different anions due to the absence of extensive tribocorrosion processes.

Application of Biodegradable Cutting Fluids in High Speed Turning

Large quantities of coolant-lubricants are still widely used in metal working industry, generating high consumption and discard costs and impacting the environment. An alternative to current practices is to use biodegradable cutting fluids that doesn’t pollute environment or require new setups. In current study, biodegradable base oils, synthetic ester and castor oil, are chosen and compounded into cutting fluids which correspond with the national standards. The tests have been performed to high speed turn AISI 1045 steel in ester-based fluid, castor-based emulsion, kerosene and dry condition. The results indicate that the application of cutting fluids is inevitable in metal machining and can not be replaced by dry machining. The lubricating and cooling properties of the ester-based fluid and castor-based emulsion are better than kerosene and can wholly replace mineral oil.

Investigation of tool wear and surface integrity on MQL machining of Ti-6AL-4V using biodegradable oil

Minimum quantity lubrication (MQL) machining involves the application of small quantity of lubricant to the tool–workpiece interface. This paper describes the results of an investigation on the effects of using different MQL lubricants (synthetic ester and palm oil) on the drilling of Ti-6Al-4V. Dry cutting was also performed for comparison purposes. It was found that drilling under dry conditions resulted in the shortest tool life due to severe chipping. MQL is beneficial to the measured responses such as tool life, thrust force, torque, and temperature. The outstanding performance of palm oil in reducing the value of those responses was attributed to its ability to form a thin film which promoted boundary lubrication during the machining process. The presented results indicated the substantial benefit of using palm oil in terms of microhardness, surface roughness, and subsurface deformation. This work shows that palm oil can be used as a viable alternative to a synthetic ester as a MQL lubricant.

Mono- and diesters of N-benzoylaminoacetic acid as antiwear additives to synthetic oils

Mono- and diesters of N-benzoylaminoacetic acid, which exhibit high wear-preventive properties in a synthetic ester oil, were synthesized.

The Influence of Lubrication on Two-body Abrasive Wear of Sealing Elastomers Under Reciprocating Sliding Conditions

Elastomeric seals are prone to failure caused by abrasion during sliding against rough surfaces. In this research, the two-body abrasive wear of some selected sealing elastomers (nitrile rubber, hydrogenated nitrile rubber, acrylic rubber, and fluoro rubber) in dry and lubricated conditions has been studied. The influence of three different oils (synthetic ester, polyalphaolefin, and mineral oil) on the abrasive wear of the elastomers, at varying normal load and abrasive particle size, has been studied. The results show that, depending on the material, lubricant, abrasive size, and normal load, the abrasive wear of elastomers may increase or decrease in the presence of lubricants, and in most cases, the abrasive wear in the lubricated condition is higher than that in the dry condition. The influence of lubricant on the increase in abrasive wear is more significant during sliding against fine abrasives. Apart from the acrylic rubber, increase in the abrasive wear in presence of the synthetic ester is higher than those in presence of the mineral oil and polyalphaolefin.

Improvement of pour point and oxidative stability of synthetic ester basestocks for biolubricant applications

For environmental reasons, as well as the dwindling source of petroleum, a new class of environmentally acceptable and renewable biolubricants based on plant oils is available. Even though plant oils possess excellent lubricant-related properties, there are some concerns about using it as biolubricant base oil. In this study we present a series of structures derived from oleic acid to be used as synthetic biolubricant basestocks. Measuring of pour point (PP), flash point, viscosity index (VI), oxidation onset temperature (OT) and signal maximum temperature (SMT) was carried out for each compound. Furthermore, the friction and wear properties were measured using a high-frequency reciprocating rig (HFRR). The resulting product structures were confirmed by NMR and FTIR spectroscopic analysis. The results showed that ethylhexyl 9-(octanoyloxy)-10-(behenoxy)octadecanoate with behenyl mid-chain ester exhibited the most favorable low temperature performance (PP −48°C) and ethylhexyl 9-(octanoyloxy)-10-(octyloxy)octadecanoate octyl mid-chain ester exhibited higher oxidation stability (OT 142°C) than the other synthetic ester oils. On the other hand, the highest ball wear scan diameter was obtained for ethylhexyl 9-(octanoyloxy)-10-(behenoxy)octadecanoate while the lowest value was obtained for 9-hydroxy-10-octyloxyoctadecanoic acid. Overall, it was concluded that these synthetic ester oils have potential in formulation of industrial fluids for different temperature applications.

New unsymmetrical complex diesters of adipic acid considered as tribological fluids

AbstractThe paper presents results concerning the synthesis and characterisation of some unsymmetrical diesters of adipic acid with a mixed, complex structure in order to produce synthetic ester oils with specific tribological properties. These complex diesters have been synthesised by taking into account medium and superior aliphatic alcohols, such as n‐butanol, n‐hexanol, 2‐ethyl‐hexanol, isodecanol and isotridecanol along with special alcohols of a complex alkyl–aryl nature, namely 2‐phenoxy‐ethanol, 2‐([o‐sec butyl] phenoxy) ethanol and 2‐([p‐nonyl] phenoxy) ethanol, respectively. By varying the length of the aliphatic alcohols and also by modifying the length and position of the alkyl pendant group on the aromatic ring of the complex alkyl–aryl alcohols, three series of products have been realised. On the basis of this programme, it has been possible to obtain fluid products that show valuable tribological features with adequate and versatile characteristics. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Effect of MQL Liquids on Surface Integrity when High Speed Drilling Titanium Alloy

This paper describes the results of application of different MQL liquids (synthetic ester and palm oil) to high speed drilling of Ti-6Al-4V. The investigation was focused on the surface integrity of the machined surface. It was found that palm oil could be a viable alternative to the synthetic ester for MQL liquid application.

Friction evaluation of elastomers in lubricated contact

AbstractFriction testing of elastomers in lubricated contact is discussed with a focus on developing experimental arrangements that can produce worthwhile results. Practical issues unique to elastomers are covered as well as their solutions, including contact mechanics, material response to loading, contact edges, oil absorption, cleaning and specimen geometry. A critique of reciprocating laboratory testing machines, including high‐frequency short stroke and low‐frequency long stroke friction and wear machines, is conducted for their usefulness, as is critical analysis of a wide variety of specimen configurations with the aim of helping the laboratory experimenter to overcome many of the pitfalls associated with testing of elastomers in lubricated conditions. Results from experiments using various testing arrangements are analysed, and it is found that the synthetic ester and mineral oil used produced similar results. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Lubricated PVD CrAlN and WC/C coatings for automotive applications

Demand on a better efficiency and higher performance under environmentally friendly aspects is an actual trend for automotive applications and machine components. This can be achieved by vacuum coatings such as DLC (diamond-like carbon), which offer excellent results in e.g. fuel injection systems, piston pins, gears and bearings. Nowadays, DLC has become very interesting for lubricated tribological contacts, because of its outstanding tribological performance under boundary lubrication conditions, which provides low friction losses and high wear resistance. Similar to DLC CrAlN promises performance increase especially in lubricated tribological contacts, where high ductility and wear resistance are needed. Surface properties of DLC and CrAlN coatings are not analogous to uncoated steel surfaces; thereby their wettability with lubricants is different from that of conventional steel surfaces. Hence, finding an optimum PVD (physical vapor deposition) coating/lubricant pair is still a challenge with regard to improvement of system performance and efficiency. In this study the wettability of selected PVD coatings with different lubricants and the effect of their wettability on their tribological behavior were investigated. The PVD coatings are WC/C and CrAlN; the lubricants are polyalphaolefin, polyglycol, synthetic ester and mineral oil, which are mixed with the additives ZnDTP, MoDTP and S-P. The wettability of the PVD coatings with lubricants is characterized by means of adhesion energy. The tribological tests were carried out using a pin-on-disk and twin disk tribometer. The friction behavior of PVD coatings and their wettability with the lubricants were compared. It is found that the wettability of the PVD coated surface can be optimized by means of adapting the adhesion energy, which in return leads to an optimized friction behavior.

B11 Performance of Palm Oil as MQL Fluid during High Speed Drilling of Ti-6Al-4V(Advanced machining technology)

This paper presents an experimental investigation on the performance of a synthetic ester and palm oil during high speed drilling (HSD) Ti-6Al-4V using minimal quantity of lubricant (MQL) method. Tool wear, wear mechanism, cutting forces and surface integrity were monitored during the machining trials. In order to study the ability of the cutting fluids, temperature was measured during drilling process using a thermocouple wire. Both the synthetic ester and palm oil present comparable performance in terms of tool wear. In addition, palm oil outperformed synthetic ester in terms of cutting forces and workpiece surface integrity due to its ability to reduce the temperature during the drilling process.

Minimal quantity lubrication-MQL in grinding of Ti–6Al–4V titanium alloy

Titanium and its alloys are attractive materials due to their unique high strength–weight ratio that is maintained at elevated temperatures and their exceptional corrosion resistance. The major application of titanium has been in the aerospace industry. On the other hand, titanium and its alloys are notorious for their poor thermal properties and are classified as difficult-to-machine materials. The problems that arise during grinding of titanium alloys are attributed to the high specific energy and high grinding zone temperature. Significant progress has been made in dry and semidry machining recently, and minimal quantity lubrication (MQL) machining in particular has been accepted as a successful semidry application because of its environmentally friendly characteristics. A number of studies have shown that MQL machining can show satisfactory performance in practical machining operations. However, there has been few investigation of MQL grinding of special alloys like titanium alloys and the cutting fluids to be used in MQL grinding of these alloys. In this study, vegetable and synthetic esters oil are compared on the basis of the surface quality properties that would be suitable for MQL applications. The cutting performance of fluids is also evaluated using conventional wet (fluid) grinding of Ti–6Al–4V. As a result, synthetic ester oil is found to be optimal cutting fluids for MQL grinding of Ti–6Al–4V.

Analyses of the Long-Term Performance and Tribological Behavior of an Axial Piston Pump Using Diamondlike-Carbon-Coated Piston Shoes and Biodegradable Oil

This work reports on the performance enhancement of a real-scale hydraulic system consisting of diamondlike-carbon (DLC)-coated components in combination with biodegradable oil in long-term experiments under conditions simulating those in an actual application. The performance of a hydraulic axial piston pump with DLC-coated piston shoes was evaluated in a newly designed, dedicated hydraulic test system using fully formulated biodegradable, synthetic ester oil. For comparison, an equal but separated hydraulic system with a conventional commercial pump and stainless-steel shoe surfaces was tested. The tests were run at 85% of the maximum pump load and an oil temperature of around 80°C for a period of 2000h, which corresponds to more than 1yr of continuous 8h∕day operation in an application. A major abrupt oxidation-induced degradation of the oil did not occur in either system; however, the oil from the system comprising the DLC-coated shoes showed noticeably and consistently better results. The wear of the DLC-coated shoes, especially during the running in, was much lower than that in the conventional steel system. Only minor polishing wear was observed on the DLC shoe’s sliding surfaces during the test period, while on the steel shoe’s surfaces, many scratches were found and some erosion of the edges was detected.

Experimental Study on Ignition and Combustion Behaviors of Insulation Fluids for Transformer using Cone Calorimeter

Silicone liquid has the high performance in fire safety showing fire resistance by self-extinguishing, and that is less environmentally pollutant compared with mineral oil. Applicability of silicone liquid of 20cSt to transformers was investigated from the view point of the correlation of ignition time with critical radiant heat flux. The same tests were carried out using a mineral oil and synthetic ester oil. The basic properties of silicone liquid (20cSt) obtained from the series of the tests were verified in its application as a less-flammable transformer fluid.

Synthetic lubricants based on sebacic complex esters

AbstractThis paper presents the results of a study carried out in order to produce synthetic ester oils of a mixed structure based on sebacic acid with beneficial tribological properties. These series of unsymmetrical diesters were synthesized using superior aliphatic alcohols such as 2‐ethyl‐hexanol, isodecanol and isotridecanol, along with special alcohols of a complex alkyl‐aryl structure, namely 2‐phenoxy‐ethanol, 2‐[(o‐sec butyl) phenoxy] ethanol and 2‐[(p‐nonyl) phenoxy] ethanol. Also synthesized were symmetric esters based on the complex aliphatic‐aromatic alcohols with pendant aliphatic chain. The variation in the principal properties as a function of both the length of the aliphatic chain introduced by the aliphatic alcohol, and the length and position of the aliphatic pendant chain on the aromatic nucleus of the complex alkyl‐aryl alcohol was assessed. Based on this, it has been possible to obtain fluid products with variable properties. The introduction of the aromatic function in the structure of these diesters led to interesting features, and the superior values recorded for the main tribological characteristics demonstrated their versatility. Copyright © 2006 John Wiley &amp; Sons, Ltd.