Lubricant Base Research Articles

A Methodological Approach to Assessing the Tribological Properties of Lubricants Using a Four-Ball Tribometer

Based on the analysis of standards for the testing of lubricants, both liquid and plastic, on a four-ball tribometer, and the analysis of the parameters by which lubricants are evaluated, this paper proposes a methodology and an integral parameter for the estimation of tribological properties. The methodological approach proposed in this paper allows for the integration of a variety of parameters provided in the standards for the testing of lubricants into one indicator. Herein, we show that the developed technique is based on the energy approach and takes into account the specific wear work of the test material (steel balls) in the lubricating medium to be investigated. The results of laboratory tests of a wide range of lubricants are presented: hydraulic fluids, motor and transmission oils of various purposes and classifications. It is shown that the magnitude of the integral parameter can be used to assess the effectiveness of anti-wear and anti-scuff additives in base lubricants, as well as the ranges of their applications. This allows for differentiation and quantitative evaluation of the effectiveness of such additives. The obtained results allow us to state that all tests according to the developed method are reproducible and homogeneous, which is confirmed using the Cochran criterion. The coefficient of variation during testing does not exceed 18%. We show that the presented methodology and the integral parameter can be used in the first stage of the laboratory selection tests of new lubricants and additives of various origins, reducing the costs of their development and implementation.

Heating repairable superamphiphobic coatings for long-lasting antifouling application

Superamphiphobic materials exhibit broader applications and possess greater potential compared to their superhydrophobic counterparts. Therefore, it is crucial for superamphiphobic coatings to exhibit applications while maintaining a long service life. To address this challenge, the surface of natural clay kaolin particles was modified through the reaction of ethyl orthosilicate and 1 H, 1 H, 2 H, 2 H -perfluorodecyl triethoxysilane to form organic-inorganic cage fluorinated polyhedral oligomeric silsesquioxane (fluoroPOS) modifiers. Subsequently, antimicrobial ZnO nanoparticles were prepared in situ using hydrothermal methods. Finally, a durable superamphiphobic coating was achieved by physical blending of a polydimethylsiloxane (PDMS) solution with the superamphiphobic powder. Experimental results demonstrate that the as-prepared ZnO/kaolin@fluoroPOS/PDMS coatings are resistant to water, milk, coffee, soy sauce, tea, sunflower oil, lubricant base oils, and other everyday liquids at contact angles greater than 150 degrees, demonstrating superior superamphiphobic and self-cleaning properties. Moreover, the coatings can withstand harsh external environments such as strong acid and alkali chemical corrosion, high temperature heating, photo-radiation aging, mechanical friction and wear, and show good durability. More importantly, the low surface energy fluoroPOS can spontaneously migrate from the interior of the coating to the surface when exposed to heat, thus restoring their impaired superamphiphobic properties. The coatings also have good antimicrobial adhesion due to the incorporation of ZnO nanoparticles. In addition, coatings can be fabricated on a variety of soft and hard substrate materials, such as cotton fabrics, sponges, aluminum sheets, and wood. Therefore, the repairable and durable superamphiphobic antifouling coatings constructed in this study are expected to find applications in many areas, such as building coatings, oil and gas pipelines, fluid drag reduction, and biological anti-corrosion.

Polyols from castor oil (Ricinus communis) and epoxidized soybean oil (Glycine max) for application as a lubricant base

AbstractPolyols are widely synthesized from fossil sources and applied in multiple sectors of the industry as raw material for polyurethane production and also as lubricants. Although the preparation method normally used is efficient and practical, it is necessary to develop environmentally friendly synthesis route that reduce pollution. This study focuses on an alternative synthetic route for the synthesis of polyols using only raw materials from renewable sources. Polyols were successfully obtained by modifying castor oil and epoxidized soybean oil through transesterification, transamidation and oxirane ring opening. The polyols were then characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H and 13C‐NMR), acidity index (AI), thermogravimetry (TGA), differential scanning calorimetry (DSC), size exclusion chromatography (SEC), dynamic viscosity and exploratory scanning of ecotoxicological parameters using Artemia salina. The results highlight the promising potential of transamidated castor oil (TACO) polyol in the field of biolubricants, attributed to its high viscosity index, oxidative stability and, ecofriendly behavior.

Effect of texture shapes and additives in lubricants on the dynamic characteristics of the hydrodynamic journal bearing

PurposeThis study aims to understand how the texture shape, number of textures and addition of nanoparticle additives in lubricants impact the dynamic characteristics of journal bearing by comparing six different texture shapes like triangle, chevron, arc, circle, rectangle and elliptical applied in pressure-increasing region under various geometrical and operating conditions.Design/methodology/approachThe finite element method approach has been employed to solve governing Reynold’s equation, assuming iso-viscous Newtonian fluid, for computation of performance parameters like stiffness and damping coefficient, threshold speed, etc. By using a regression model, the impact of adding nanoparticles Al2O3 and CuO to the base lubricant on viscosity variation is calculated for selected temperature ranges and weight fractions of nanoparticles.FindingsThe arc-shaped texture with an area density of 28.27%, eccentricity ratio of 0.2 and texture depth of 0.6 exhibited 35.22% higher direct stiffness and 41.4% higher damping coefficient compared to the lowest value in the circle-shaped texture. Increasing the number of arc-shaped textures on the bearing surface with low area density led to declining stiffness and damping parameters. However, with nanoparticle additives, the arc-shaped texture further showed 10.75% and 8.11% improvement in stiffness and 9.99% and 4.87% enhancement in damping coefficient for Al2O3 and CuO, respectively, at 90 °C temperature and 0.5% weight fraction.Originality/valueBy understanding the influence of texture shapes on the dynamic characteristics, engineers can design bearings that exhibit improved stability and enhance overall performance.

Synthesis of the Antioxidant Compounds from the Eugenol to the Lubricating Oils

In this study new antioxidant compounds were prepared by (thiol-ene) click chemistry, where these compounds were prepared using (1:1) mole ratio of (thiol : eugenol) in the presence of benzoyl peroxide as initiator and the reaction is carried out at (100 0C) for (9) hrs. 
 (FT-IR), (1HNMR), and mass spectroscopy were used to characterize the synthesized compounds. They were evaluated as antioxidants by adding compounds to base oil and lubricant oil, where they showed high antioxidant activity against lubricant oil oxidation processes.

DFT Calculation of the Mechanism of the Acid-Catalyzed Aldol Condensation of a Lubricant Base Stock

Aldehyde condensation is a reaction step in the oxidization of a lubricant base stock into high-molecular-weight products, forming sludge and a paint film, which lead to the failure of lubricating oil. Calculations on the basis of the density functional theory (DFT) were employed to investigate the reaction mechanism of the acid-catalyzed aldol condensation of a lubricant base stock. Carbonyl compounds could be converted into their resonant enol structures. However, the activation energy of the process was relatively high, and it was difficult to initiate. The existence of the acid could obviously decrease the activation energy of the reaction from 269.17–287.82 kJ/mol to 177.10–177.63 kJ/mol, and it significantly reduced the difficulty of initiating this reaction. The carbocation formed by the carbonyl compounds and acid could further react with the enol and produce an intermediate reaction product in which the chain of molecules grew longer. This process was not difficult to initiate, with a reaction activation energy of 65.10 kJ/mol. The intermediate product with a larger molecular weight could be converted into carbonyl compounds containing a β-hydroxy by removing a hydrogen proton from it. The energy barrier for this process was 193.15 kJ/mol, and it was not easy to initiate the reaction.

MMP Net: A feedforward neural network model with sequential inputs for representing continuous multistage manufacturing processes without intermediate outputs

Machine learning models that are used for the prediction and control of production can improve quality and yield. However, developing models that are highly accurate and reflective of real-world processes is challenging. We propose a feedforward neural network model specifically designed for continuous Multistage Manufacturing Processes (MMPs) without intermediate outputs. This model, which is termed “MMP Net,” can accurately represent the control mechanism of continuous MMPs. Whereas existing studies on learning MMPs assume an intermediate output data, the MMP Net does not require such an unrealistic assumption. We use the MMP Net to develop prediction models for the lubricant base oil production process of a world-leading lubricant manufacturer. Evaluation results show that the MMP Net is superior to other deep neural network and machine learning models. Consequently, the MMP Net was actually implemented in a real factory in 2022 and is expected to save 900,000 dollars per year for each production line. We believe that our work can serve as a basis to develop customized machine learning solutions for improving continuous MMPs.

Lubrication mechanisms of dispersed carbon microspheres in boundary through hydrodynamic lubrication regimes

HypothesisCarbon microspheres have been shown to reduce friction and surface wear at relatively low speeds and high applied loads (i.e., within the boundary lubrication regime). We hypothesize that in dilute colloidal lubricating systems there is an interplay between the size of the carbon microspheres and the lubrication gap size, which determines the dominant lubricating mechanism of the system. ExperimentsA 60 wt% aqueous glycerol solution was used as the base lubricant and compared to various carbon particle-based lubricant formulations ranging in particle concentrations from 0.05 to 0.30 vol%. The tribological properties of the various lubricant formulations were tested on a pin-on-disk tribometer. A simplified Stribeck plot was produced to understand the changing mechanism of lubrication over a wide range of conditions. FindingsThe Stribeck curves show that the carbon microspheres assist lubrication by a rolling mechanism primarily in the boundary lubrication regime. A 0.20 vol% carbon-based lubricant formulation showed the best friction reduction compared to the base lubricant. Increasing speed increases the lubricating gap between the friction pair beyond the size of the particles, thereby nullifying the rolling mechanism of the particles. We introduce a modified specific film thickness parameter to determine the lubrication regime in a particle-lubricant system.

Tribological Performance Evaluation of Blended Lubricants Incorporated with Organic Polymer

Eco-friendly lubricants have drawn a lot of interest in the lubrication industry as a way of promoting global sustainability in response to the growing environmental pollution danger posed by the use of petroleum-based lubricants. As a result of these, developing lubricants with organic additives stands as a promising technique in solving the environmental challenges caused by non-degradable materials. This research investigates the effect of bio-based water hyacinth (Eichhornia crassipes) (EC) carboxylmethyl cellulose (CMC) polymer in different base lubricants as well as under different volumetric blend to determine their compatibility effect on lowering friction and wear using base rapeseed oil (BRO) and mineral oil (MO) as a base lubricant sample. High frequency reciprocating rig tribo-tester machine was used in the experiment, followed by substrate surface analysis via energy dispersive x-ray spectroscopy. The additives were evaluated for their potential to improve tribology in terms of friction, surface roughness and wear reduction, load-carrying capacity, and mechanism of repair. Testing the additive concentrations, produced recommendable result at 0.8 mass% EC-CMC. The best performance was obtained when BRO70/MO30 was blended with 0.8 mass% EC-CMC. When compared to base BRO and MO lubricants under 80 N, 0.8 mass% BRO70/MO30 reduced the coefficient of friction and wear scar diameter by 44%, 32%, and 33%, 21% respectively. However, it was shown that nanoparticles had greater tribological performance at higher working capacities owing to the rapid and active tribo-film formation.

Biodiesel Promotes Iron-Catalyzed Oxidation of Engine Lubricating Oil

The growing trend of increasing biodiesel concentrations in diesel fuel blends has led to concerns about its effect on the oxidation of formulated oils within internal combustion engines. We observe that biodiesel is not only susceptible to rapid oxidation at elevated temperatures but is also responsible for acceleration of the oxidation process of the lubricant base oil when in the presence of soluble iron; this is supported by a range of control and model experiments. A mixture of oxidized biodiesel and Fe(III) leads to the formation of catalytic iron carboxylate networks that remain solubilized, as observed by UV–Vis and infrared absorption studies. These observations are important for the fundamental understanding of the chemistry within industry standard laboratory bench tests for lubricant oil formulations and can aid the design of new lubricants with improved biodiesel compatibility. Such lubricants have the potential for a reduced carbon footprint via waste reduction.

A Review on Bio-Lubricants as an Alternative Green Product:Tribological Performance, Mechanism, Challenges and Future Opportunities

Industries, especially those related to transportation, have relied extensively on petroleum products for lubrication, raising serious questions about the security of the world energy supply in the future. Observed that the end-products might be released back into the environment, posing major environmental risks. As a result, bio-based products have attracted increasing interest as prospective replacement to mineral-based type due to their important role in resolving the issues of pollution. With renewability and biodegradability as their greatest points, bio-based lubricants have been discovered to offer superior lubricating qualities to those of traditional mineral lubricants but currently have some undesirable qualities that need to be improved based on the literatures. Therefore, this research objective is to showcase the potential of bio-lubricants, both in terms of their environmental benefits and for technical applications, based on studies that have been published over the years. Review of the natural oil's molecular structures, physio-chemical characteristics, and lubricating ability is crucial for the creation and choice of lubricants. Owing to their accessibility in a wide range of characteristics, which are necessary for specific applications, bio-based lubricant is a possible replacement for a variety of applications, according to the primary findings. The results showed that sunflower oil improved in reducing friction and wear by 93.7% and 70.1%; and 77.7% and 74.1%, under TiO2 and SiO2 studied, against base lubricant values of 0.0511 and 11.2414 (mm3), respectively. However, to get beyond some of the restrictions such as poor low temperature and oxidative stability, adequate chemical modification is necessary in solving agglomeration challenges.

N-doped Metallocene Catalysts for Synthesis of High Quality Lubricant Base Oils from Fishcher–Tropsch Synthesized α-Olefin

N-doped Metallocene Catalysts for Synthesis of High Quality Lubricant Base Oils from Fishcher–Tropsch Synthesized α-Olefin

Green synthesis of trimethylolpropane triisostearate and triisooleate for usage as bio-lubricants

Two methyl-branched triesters, trimethylolpropane-triisostearate (TMP-ISA) and trimethylolpropane-triisooleate (TMP-IOA) have been synthesized via esterification of trimethylolpropane with isostearic-acid and isooleic-acid, respectively. Isostearic-acid and isooleic-acid have been previously produced through the skeletal-isomerization reaction of naturally derived oleic acid using a reusable zeolite catalyst. TMP-ISA and TMP-IOA are characterized by FTIR NMR, GC-MS, and LC-MS. Physicochemical and tribological analysis reveal that TMP-ISA and TMP-IOA exhibit higher oxidative stability, viscosity index, anti-wear property, and better cold flow properties when compared to high-oleic sunflower oil or polyalphaolefin, a common lubricant base oil. Lubricant property analysis of blends of TMP-ISA or TMP-IOA with high-oleic sunflower oil or polyalphaolefin demonstrates their miscibility and potential applications as biolubricants. Upon commercialization, these developed bio-based esters have the potential to reduce the existing reliance on non-renewable petroleum based lubricants. Practical applicationMethyl-branched triesters with trimethylolpropane backbone exhibit promising physicochemical and tribological properties to be used as bioingredients in bioproducts.

Lubricity effectiveness of bio-lubricant modified with multi-wall carbon nanotube and organic polymer

The development of effective bio lubricants with anti-friction and wear properties is gaining recognition due to their ecofriendly nature and good lubrications in mitigating challenges associated with friction and wear on tribo-components during lubrication. In this research, rapeseed oil served as the base lubricant, and the high frequency reciprocating rig was utilized to examine the responsiveness of the multiwall carbon nanotubes (MWCNTs) and Eichhornia crassipes carboxylmethyl cellulose (EC-CMC) polymer additives. To determine the constituents and strength of the formulations, the samples were characterized using scanning electron microscope, Energy-dispersive X-ray, Fourier transform infrared spectroscopy, Raman, and X-ray photoelectron spectroscopy. The tribological test was conducted in terms of synergistic tendency, load carrying capacity, friction and wear reduction as well as tribo-film nature. The investigation came to the following conclusions: Depending on the operating conditions, all nanoparticle suspensions showed decreases in friction and wear relative to the base oil; MWCNTs yielded better wear reduction performance while EC-CMC demonstrated outstanding friction reduction operations compared to based lubricant; the suspensions with 0.8% MWCNTs +0.5% EC-CMC had the best tribological behavior, exhibiting high percentage reduction on friction (67.8%) and wear (37.9%) with low levels on the surface roughness. Using XPS analysis, the detection of additive elements and tribo-films on the wear surfaces was validated, and their nature was analyzed in the context of the related tribo-chemistry findings. The study concluded that effective friction reduction during testing is a result of the additive's rapid penetration into the interface region and its nanosized structure.

Tribological Behavior of Doped DLC Coatings in the Presence of Ionic Liquid Additive under Different Lubrication Regimes

Diamond-like carbon (DLC) coatings are widely used in industries that require high durability and wear resistance, and low friction. The unique characteristics of DLC coatings allow for the possibility of creating adsorption sites for lubricant additives through the doping process. In this study, the combined use of europium-doped diamond-like carbon (Eu-DLC), gadolinium-doped diamond-like carbon (Gd-DLC), and pure DLC coatings and an ionic liquid (IL) additive, namely, trihexyltetradecylphosphonium bis (2-ethylhexyl) phosphate [P66614] [DEHP], with a 1 wt.% concentration in polyalphaolefin (PAO) 8 as a base lubricant was investigated. Higher hardness, higher thin-film adhesion, a higher ratio of hardness to elastic modulus, and a higher plastic deformation resistance factor were achieved with the Gd-DLC coating. The CoF of the Gd-DLC coating paired with the IL was superior compared to the other pairs in all lubrication regimes, and the pure DLC coating had a better performance than the Eu-DLC coating. The wear could not be quantified due to the low wear on the surface of the DLC coatings. The friction reduction demonstrates that tribological systems combining Gd-DLC thin films with an IL can be a potential candidate for future research and development efforts to reduce friction and increase the efficiency of moving parts in internal combustion engines, for instance.

Study Comparing the Tribological Behavior of Cottonseed and Castor Oil Biodiesel Blended Lubricant under varying Load Conditions

Abstract: We have an increasing global need for bio lubricants that are safe for human and environmental use, easily biodegradable, and non-polluting. The friction and wear qualities of cotton seed blended lubricant as well as castor blended lubricant are compared and contrasted in this research using a Pin on disc wear testing Tribometer. In this research, we will look at the study's results and analyse their significance. Blended lubricants were created by combining cotton seed & castor based biodiesel with the basic lubricant SAE20W40 at volumetric ratios of 5, 10, 15, & 20%. Cotton seed and castor blended bio lubricants were tested for friction and wear at sliding velocities of 2.5 metres per second while subjected to weights of 50 N, 100 N, and 150 N. Wear might be slowed by as much as 15 percent by mixing in cotton seed biodiesel with the base oil, as has been shown. When this threshold is passed, wear increases at an ever-increasing pace. Castor oil blended lubricant performed best in wear tests when coupled with a base lubricant at a 5 and 10 percent castor oil blended lubricant concentration. The wear rate was accelerated when 15 percent castor oil was added to the basic lubricant. It has been discovered that at lowest and maximum load, CBL 5 and CBL 10 may serve as an alternative lubricant to increase mechanical efficiency at a sliding velocity of 2.5 metres per second. Because of their efforts, less need has been seen to lessen dependence on petroleum-based goods.

Influence of Some Additives on the Efficiency of Viscosity Index Improver for Base Lubricating Oils

The effects of three different additives formulations namely Lubrizol 21001, HiTEC 8722B and HiTEC 340 on the efficiency of VII namely OCP of three base lubricating oils namely 40 stock and 60 stock and 150 stock at four temperatures 40, 60, 80 and 100oC were investigated. The efficiency of OCP is decreased when blended with 4 and 8 wt% of Lubrizol 21001 for all the three base oil types. But it is increased when adding 4 wt% and 8 wt% of H-8722B in 40 stock. While for 60 stock and 150 stock the OCP efficiency decreased by adding 4 and 8 wt% of H-8722B. In the other hand, it is decreased with a high percentage by adding 4 and 8 wt% of H-340 for 60 stock and 150 stock and for 40 stock it is increased by adding 4 wt% of H-340 and decreased with insignificant percentage when adding 8 wt%. Finally, a number of VI correlations have been obtained depending on the results predicted in this study. These correlations represent the functional relationships between the VI and the concentration of OCP for three types of base lubricating oil and for each type of additives.Keywords: Lubricating oil, Kinematic Viscosity, Viscosity

Base lubricants for green stamping: The effects of their structure and viscosity on tribological performance

The requirements for green and sustainable manufacturing mean that stamping lubricants must be continuously re-evaluated and re-designed. In this investigation, the tribological performance of four base oils with different chemical structures (paraffinic and naphthenic) and viscosities (2 and 20 cSt), as well as water, was evaluated for the stamping of steel sheets and compared with a non-lubricated contact. Most lubricants reduce the coefficient of friction and maintain a similar wear coefficient for steel sheets as in dry contacts. Low-viscosity (LV) naphthenic oil performs very like both high-viscosity (HV) oils. A surprising exception is the LV paraffinic oil, with several-times-higher friction and wear compared to dry contact. This is due to the excellent wetting-spreading and very low cohesion forces that enable oil to escape from extremely thin-film contacts because the viscosity is so low, leading to lubricant starvation. In contrast, HV oils provide a sufficiently thick lubricating film, while strong cohesive forces help in the film’s strength, lessening wear, and reducing friction. In thin-film lubrication with LV oils, such as when stamping, it is thus extremely important that the lubricant’s wetting behaviour and viscosity are sufficient to provide enough film in the contact and prevent starvation, thus ensuring lower friction, less wear, and a longer lifetime of the contact.

Intrinsic relationship between viscosity, viscosity index, and molecular structure of isoalkanes.

Viscosity and viscosity index are the crucial properties of lubricant base stocks. Molecular dynamics simulation and quantum calculation were used to simulate the five isomers of C26H54 to study the intrinsic relationship between viscosity, viscosity index, and the molecular structure of isoalkanes. The results showed that the intermolecular interaction energy and the volume of rigid-like groups were the intrinsic factors that affected the viscosity and which could describe the viscosity quantitatively. The molecule conformation was studied by calculating the rotational energy barrier of the dihedral angle in the isoalkane molecule, and combined with molecular dynamics, the effect of temperature on the molecular conformation at 313K and 373K was further investigated. The α, β, and γ carbon atoms adjacent to the tertiary carbon in the isoalkane molecule were difficult to rotate due to steric hindrance and could be regarded as rigid-like groups at 313K. The tertiary carbon and the three adjacent carbon atoms formed a regular tetrahedral rigid-like group at 373K. The changes in the intermolecular interaction energy and the volume of the rigid-like group with temperatures could better describe the viscosity index and reveal the fundamental reasons that affect the viscosity and the viscosity index. The molecular-level understanding of the relationship between the molecular structure and properties of isoalkanes provided theoretical support and scientific guidance for designing isoalkane molecules with specific properties. Molecular dynamics simulation and quantum calculation were performed using Material Studio 8.0 software. The Amorphous Cell module was used to create an amorphous cell. The Foricite module was used for molecular dynamics simulation; the forcefield was assigned as COMPASS II. Nose-Hoover thermostat and Berendsen barostat were applied to maintain the temperature and pressure, respectively. To describe the non-bond interactions, the Ewald method was applied to calculate the van der Waals and electrostatic interactions. The Conformers module was used to study the conformation and the Dmol3 module was used to calculate the conformational energy with fine quality; the functional of GGA-PW91 and the basis set of DNP were used to calculate the energy.

Investigation of Thermophysical and Rheological Properties of Scallop Shell Powder/SAE 5w-30 Nanolubricant

Nanolubricant is a type of nano fluid that contains base-fluid lubricant (water or oil) and nanoparticles. This study aims to analyze the thermophysical and rheological properties of lubricants with the addition of nanoparticles. The nanoparticles used are Calcium Carbonate (CaCO3) made from scallop shell waste. The base lubricant is SAE 5W-30 synthetic oil which has quite good performance. Synthesis of Calcium Carbonate (CaCO3) into SAE 5W-30 lubricant uses a two-step method. Variations in the addition of volume fraction of Calcium Carbonate (CaCO3) of 0.05%, 0.10%, 0.15%. Furthermore, the nanolubricant was tested for its thermophysical properties which included thermal conductivity, specific heat, density, viscosity, and sedimentation. After that, the rheology of the nanolubricant can be known from the viscosity data by calculating the shear rate and shear stress.