Nano Lubricant Research Articles

The Role of Functionalized CuO Additive in Enhancing Tribological Performance of Plastic Oil Lubricant

ABSTRACTThe study investigated the potential of waste plastic oil (PO) as an alternative to petroleum‐based lubricants, specifically mineral oil. The rheological properties, dispersion stability, friction, and wear performance of PO were examined and compared with mineral oil. Results showed that PO demonstrated similar lubrication performance to mineral oil. To enhance the lubrication performance of PO, the study incorporated various concentrations of nano CuO solid lubricant additives, resulting in the formation of CuO nano lubricants. These lubricants showed an improvement in friction and wear by 20% and 44% compared with PO. Furthermore, the CuO solid lubricant additives were functionalized and incorporated in the same concentrations into PO, resulting in the formation of functionalized nano lubricants, which further lowered the friction and wear by 28% and 91% compared with PO. The novelty of the paper is that a simple chemical functionalization process that not only helped in improving its dispersion stability of additives in the PO, but also enhanced the wear performance. The mechanisms behind the enhancement of friction and wear performance were discussed. Based on these findings, it can be concluded that incorporating functionalized nano additives in PO improve friction and wear performance in mechanical components, promoting wider utilisation of PO.

Fabrication of Surface-carbonated Boron Nitride Nanosheets and Their Application as Water-based Lubrication Additives

As a typical two-dimensional layered material, hexagonal boron nitride nanosheets (BNNSs) have high mechanical strength, good conductivity, and excellent lubrication performance, which have great potential as solid nano lubricant additives in tribology. When BNNS is used as a water-based or oil-based lubricant additive, its inherent chemical inertness and poor dispersion stability make it difficult to achieve optimal anti-friction and anti-wear performance. In this paper, a simple and efficient preparation method for obtaining hexagonal boron nitride nanosheets (C-HPC-BNNSs) with surface carbonization modification and excellent dispersion stability in water-based lubricants was proposed. Using hydroxypropyl cellulose (HPC) as a modifier, a wet ball milling process combined with high-temperature carbonization treatment effectively reduced the thickness of BNNSs while uniformly modifying N-doped carbon layers on the surface of the nanosheets. Benefit from the smaller layer thickness of C-HPC-BNNSs, they exhibit excellent dispersion stability in the water-glycol solution and can maintain no significant agglomeration behavior for up to 30 days, which is the basis for the excellent lubrication performance of lubricant systems. In addition, the N-doped carbon layer modified on the surface is beneficial for enhancing the hydrophilicity of BNNSs and synergistically enhances the tribological properties of the material with BNNSs. The test results of the four-ball friction tester show that compared with the pure water-glycol solution and the water-glycol system with added C-HPC-BNNSs, the friction coefficient (COF) and wear volume of the system with added C-HPC-BNNSs could be as low as 0.095 and 1.99 × 10-4 mm3, respectively. This work has positive significance for the preparation, surface modification, and tribological application expansion of two-dimensional layered material BNNSs, which is conducive to further understanding the relationship between.

Performance of R134a vapour compression refrigeration system by using Gr and Al2o3 hybrid nano lubricants

Nowadays, in many developing countries like India they are facing the shortage of energy. The Refrigeration system has become the major consumer of energy for many industrial as well as household applications. So, it is the need to enhance the energy efficiency of the refrigeration systems. Performance of the refrigeration system can be improved either by increasing the rate of heat absorption in evaporator or by reducing the compressor power. Use of efficient lubricant oil can help to remove the heat generated in the compression process which leads to less power consumption. Development in Nanotechnology makes it possible to develop a new class of lubricant called nanolubricant, in which nanoparticles are added in base lubricant oil to enhance the thermal properties. The two step technique with ultrasonic agitation force is used tosynthesise stable nanolubricant. The present study investigates the performance of an R-134a refrigerant vapour compression refrigeration system using nanolubricant with different volume concentrations (0.05%, 0.075%, 0.1% and 0.2%) of Graphene/Aluminium nanoparticles to mineral oil (MO) experimentally. The result shows maximum enhancement in COP approximately as 85% for 0.075 % volume fraction Nano lubricant as compared to base fluid. Use of nanolubricant saves approximately 27% compressor power.

Rheological Insights and Optimization of Bio Nano Lubricants in Tribological Systems

Rheological Insights and Optimization of Bio Nano Lubricants in Tribological Systems

Influence of additive nano calcium carbonate (CaCO3) on SAE 10W-30 engine oil: A study on thermophysical, rheological and performance

Researchers have used nanomaterials as additives in base oil to improve its specifications, especially to minimize wear and friction during its applications. In this study, calcium carbonate (CaCO3) nanoparticles were selected as an additive to serve as a protective layer between components and anti-wear properties. In this study, calcium carbonate (CaCO3) nanoparticles were selected as an additive to serve as a protective layer between components and anti-wear properties. Nano lubricant samples were prepared using mass variations of CaCO3 and SAE 10W-30 base oil with concentrations of 0.05, 0.1, 0.15, and 0.2%, then homogenized. The nanolubricant samples obtained were analyzed for thermophysical, rheological properties and lubricant performance with the addition of nano CaCO3 in improving the wear resistance of FC25 cast iron. The results of thermophysical and rheological properties analysis suggest that the nanolubricant has better tribological properties compared to base lubricants. The highest values of thermal conductivity, density, and viscosity (40 oC) are 0.139 W/m.K, 812.203 kg/m3, and 106 mPa.s (40 oC). Meanwhile, the highest CoF, disc mass loss, and surface roughness of nanolubricant are 0.0706, 0.0037 grams, and 0.50 µm, respectively. These results indicate that the greatest wear-reducing agent is from the nanolubricant with the addition of CaCO3 nanopowder additives at 0.1 wt% concentration. These results are expected to give significant insights into the advancement of nano technology-based lubricants in the future.

Exploration of linear and exponential heat source/sink with the significance of thermophoretic particle deposition on ZnO-SAE50 nano lubricant flow past a curved surface

The present research focuses on exploring the impact of linear and exponential heat source/sink on double-diffusive MHD convective flow heat and mass transport of ZnO – SAE50 nano lubricants in an exponentially stretching curved sheet along with the effect of thermophoretic particle deposition. The heat transmission is considered to be caused by both radiation and convection. The mathematical modelling of the considered problem results in a coupled system of partial differential equations, using suitable similarity transformation variables these equations are reduced to a coupled non-linear system of ordinary differential equations and are solved numerically by adopting the finite difference method to obtain the solution for the field variables. The quantity and spatial distribution of linear heat sources/sinks affect the physical dynamics and optimum status of the entire system and the application of exponential heat sources/sinks can improve heat dispersion and energy efficiency in industrial operations such as nuclear reactors and steel production. The thermophoretic particle deposition parameter controls particle concentration by allowing particles to accumulate on surfaces or in specific areas of the fluid. A rise in Hartmann number causes a mechanical damping force to act in the opposite direction of the fluid motion, lowering the speed of the fluid in the curved sheet. The heat and mass transmission properties are analyzed through the Levenberg – Marquardt backpropagating algorithm and the correlation coefficient has ideal values of unity for training, validation, testing, and overall. In light of this, the anticipated behaviour of the LMNN-BPA indicated that the heat transfer profile numerical data and the network output are in good consensus.

Enhancing Lubrication Performance of Plastic Oil Lubricant with Oleic Acid-Functionalized Graphene Nanoplatelets and Hexagonal Boron Nitride Solid Lubricant Additives

The study explored the viability of using waste plastic oil (PO) as an alternative lubricant to petroleum-based lubricants in industrial settings. To enhance the lubrication performance of the PO, this study incorporated cost-efficient, oleic acid-modified, graphene nano platelets [GNP (f)] and hexagonal boron nitride [hBN (f)] nano solid lubricant additives into the PO in various concentrations, forming functionalized nano lubricants. The PO and its functionalized nano lubricant’s rheological, dispersion stability, thermal degradation, friction, and wear performance were investigated. Results manifest that incorporating GNP (f) and hBN (f) into the PO significantly enhanced the viscosity and dispersion stability. In addition, it was seen that GNP (f) and hBN (f) nano lubricants lowered the coefficient of friction (COF) by 53% and 63.63% respectively, compared to the PO. However, the GNP (f) and hBN (f) nano lubricants demonstrated a 3.16% decrease and a 50.08% increase in wear volume relative to the PO. Overall, the GNP (f) and hBN (f) nano lubricants displayed a synergistic friction behavior, while they exhibited an antagonistic behavior pertaining to the wear volume. The study elucidated the mechanisms underlying friction and wear performance of the nano lubricants.

Improvement in Tribological Properties with Addition of Hexagonal Boron Nitride (h-BN) and Molybdenum Disulfide (MoS2) Nanoparticles in Aerospace Lubricants

In the aircraft mounted accessory gearbox and gas turbine engine gearbox, a significant rise in temperature of lubricant was consistently observed due to the high coefficient of friction (COF) between the moving parts. This phenomenon limits the speed and power transmission of the gearbox. To resolve this, the current study recommends adding specific nanoparticles (NP) as an additive to the military (MIL) grade lubricant to reduce frictional resistance between the gears. Surfactants were also added to hexagonal boron nitride (h-BN) and molybdenum disulfide (MoS2) nanolubricants (NL) to improve NP suspension. Tribological investigations were conducted with a four-ball tester, a shear stability tester, and a Reichert tester to examine the lubricants. During the four-ball test, the wear scar diameter (WSD) on the specimen decreased by 16.73% and 12.3% with h-BN and MoS2 NL, respectively, compared to the results obtained using the base lubricant (BL). In the shear stability test, h-BN NL demonstrated 93%, and MoS2 NL demonstrated 67% more shear stability than the BL, while the COF was reduced by 13% in both h-BN and MoS2 NLs during the Reichert test. These test results prove that h-BN and MoS2 NPs, when added to a MIL standard BL, can demonstrate improved tribological capabilities even at extreme operational conditions.

Nano lubricants in machining and tribology applications: A state of the art review on challenges and future trend

Nanofluids are a unique class of fluids generally prepared by adding nanosized particles to different types of base fluids, such as water, oil, etc. When nanoparticles are added to the base fluids, their thermophysical parameters like viscosity, heat transfer characteristics, and thermal conductivity are improved and provide good results. For this reason, the demand for fluids enriched with nanoparticles has considerably increased in the manufacturing sector. This comprehensive state-of-the-art review covers nanolubricants' role in friction reduction, wear resistance, and machining efficiency applications. Initially, the lubricants and their properties are revealed in the introduction section. Then, the different types of nanoparticles, their basic structure, and their different applications in machining and tribology are portrayed in different sections. In addition, it provides a comprehensive analysis of the difficulties related to nanofluids and their utilization in machining and tribology. Ultimately, this evaluation provides final comments on the latest advancements in both the academic and industrial sectors, as well as a strategy for future expansion. The results indicated that the fluids loaded with nanoparticles had a beneficial effect in lowering friction and temperature at the primary contact zone.

Influence of surface activated nanophase Pr6O11 particles on the physio-chemical and tribological characteristics of SAE20W40 automotive lubricant

In this study, the formulation of nano lubricants is undertaken through the utilization of SAE20W40 engine oil and surface-activated praseodymium oxide (Pr6O11). An analysis is conducted on the impact of concentration profile (0.1, 0.3, 0.5 wt.%) on various physio-chemical properties, including stability, viscosity, fire and flash point, calorific value, acid value, and iodine value of the nano lubricants. The wear rate and coefficient of friction are determined through the utilization of a pin-on-disc tribometer for all the synthesized nano lubricants. A comprehensive examination on the attributes of the synthesized nano lubricants is presented by means of informative images and graphs obtained from SEM, EDS, TEM, FT-IR, UV-Vis, and DSC. It is revealed that the lubricant oil containing 0.3 wt.% of Pr6O11 demonstrates superior performance when compared to the base lubricant.

Random unbalance response of rotor with CuO Nano Lubricants

Random unbalance response of rotor with CuO Nano Lubricants

CFD-FSI analysis of textured journal bearing working with nano lubricant

CFD-FSI analysis of textured journal bearing working with nano lubricant

Reducing fuel consumption of a light-duty vehicle by incorporating CuO nanoparticles in compressor lubricant of air-conditioning system

This experimental study aims to investigate the effects of copper (II) oxide (CuO) nanoparticles (~50 nm, 99.9% trace metal basis) incorporation in polyalkylene glycol (PAG) lubricant of a compressor included in air-conditioning (AC) system of a light duty passenger car. Observations on fuel consumption in real-world driving tests while the AC system is fully running were conducted. In order to determine the impacts of CuO nanoparticle incorporation in PAG oil, friction (pin-on-disc tribotester) and wear tests were carried out along with surface visualization analyses of scanning electron microscopy (SEM) and atomic force microscopy (AFM) on the disc samples laser-cut from the spare AC compressor vanes. Morphology and thermal stability of the CuO nanoparticles were also investigated via SEM and thermal gravimetric (TG) analyses, respectively. Wear rate (WR), average coefficient of friction (µa) and surface roughness analyses on the specimen surfaces were conducted to procure a comprehensive knowledge about the tribological improvement of CuO nanoparticles. All analyses were repeated on the identical metal samples in PAG lubricant bath (PL) and CuO nanolubricant (NL) separately under the same conditions and average of the test results were taken into account to minimize error. The results demonstrate that reductions of 15.5% in average coefficient of friction, 33% in wear rate and 9% in average surface roughness were achieved resulting in a decrease of 7.7% in fuel consumption at designated driving conditions.

The role of epoxidation process on improving the oxidative, thermal stability, and tribological performance of mustard oil nano lubricants

This study investigated the potential of inedible mustard oil (MO) (Brassica juncea) as a suitable bio-lubricant for enhanced thermal, oxidative stability, and tribological performance. To improve the MO's oxidative stability, it was subjected to a chemical epoxidation reaction, forming epoxidized mustard oil (EMO). The MO and EMO were evaluated for viscosity, functional groups, wettability, oxidative stability, thermal stability, friction, and wear performance. The epoxidation process resulted in nearly doubling the oxidative stability, as well as improving the thermal stability of the MO. Results showed that the EMO exhibited better lubricating properties than the MO, including lower friction and wear. To further improve the lubrication performance of the EMO, solid lubricant additives (SLAs) were incorporated in various concentrations. These SLAs were graphene nanoplatelets (GNP) and hexagonal boron nitride (hBN). The GNP and hBN nano lubricants reduced friction by 31% and 13% compared to the EMO. The same nano lubricants also lowered wear by 73% and 51% relative to the EMO. The underlying mechanisms behind the improvement in the friction and wear performance were discussed. The EMO can be considered as a suitable base stock for renewable and sustainable energy applications.

Why do hybrid nanoparticles perform better in improving heat transfer performance of lubricating oil during lubrication process: An experiment and molecular dynamics simulation

Lubricants are indispensable ingredients for alleviating friction and wear in mechanical components especially in automobile. However, due to its poor heat transfer capabilities, traditional lubricants are denatured under extreme working conditions, leading to lubrication failure during the friction process. Therefore, this study elaborately put forward to a novel MoS2/h-BN hybrid nanoparticle as efficient nano-additive for engine oil. The results of experiments and molecular dynamics simulation jointly show that compared with mono nanoparticles, hybrid nano-lubricants (NL) thermal conductivity was significantly improved than that of base oil owing to the synergistic effect. The corresponding mechanism for the improving heat transfer performance was suitably proposed based on the Mean Square Displacement (MSD) and Radial Distribution Function (RDF) results at the microscopic atomic level.

Comparing the modeling functions of hybrid nano-lubricant containing CuO and MWCNTs with standard quality measurement criteria to introduce the most optimal correlation function

One of the important properties of fluids is viscosity. In this research, the viscosity modeling of nano-lubricant (NLB) was done using RSM. Using the response surface methodology (RSM), several models including Cubic, Quartic, 2FI and Quadratic, models were designed and the relevant statistical parameters were presented. The selected model after checking the evaluation parameters R-squared, Adjusted R2, Predicted R2 and Std. Dev. is selected and the values are equal to the values of 0.9993, 0.9992, 0.9989 and 4.62, respectively. Statistical charts including residual values, normal distribution, Box-Cox and predicted values in terms of real values also introduce the best model. The trend of viscosity changes of the selected model was evaluated according to the basic parameters T, solid volume fraction and shear rate , and the temperature parameter was introduced as the most influential parameter.

Assessment on tribological responsiveness of different polymers on AISI 52100 steel using a sensitive reciprocating tribometer

Bio-based lubricants are becoming more prevalent in the lubrication sector to substitute the traditional petroleum based. In the current study, jatropha oil was used as the base lubricant with polytetrafluoroethylene (PTFE) and organic Eichhornia crassipes-carboxymethylcellulose (EC-CMC) polymers as additives. The research employed a sensitive reciprocating apparatus to examine the tribological responsiveness of the formulation on AISI 52100 steel material in terms of coefficient of friction (COF), wear rate, wear scar diameter, and surface roughness (Ra). Polymeric and Fourier transform infrared spectroscopy studies were conducted on the formulations. The findings indicate that both additives in jatropha in concentrations produced higher COF than unmodified jatropha oil at 100 and 250 r/min under low load (15 N), but improved performance under higher load (35 N). Under wear rate examination, the formulations demonstrated a slight reduction under higher working conditions; however, the 0.5 wt% EC-CMC blended sample performed poorly in terms of both COF and wear rate. In the research, 0.4 wt% PTFE and 0.3 wt% EC-CMC produced the best outcomes for their respective categories. The nano lubricant exhibited remarkable performance when tested under more demanding working conditions (500 r/min and 45 N) but performed better when 0.4 wt% PTFE was utilized, which is comparable to the reference commercial shell lubricant used. The ability of the nano lubricants to penetrate and generate some films at the sliding contact during operation shows their enhanced performance at higher operating conditions, which was supported by the results of the energy-dispersive X-ray study.

Analysis of physicochemical and tribological properties of nano alumina-based gear oil developed from effluent of lube oil blending plant

Industrial wastewater, also known as effluent has been identified as one of the leading sources of environmental pollutions worldwide. The establishment of lube oil blending plants in Nigeria has led to a continuous discharge of industrial effluent in densely populated areas. This threatens the well-being of humanity, plants, aquatic lives and construction soils. This research paper focused on developing a nano alumina-based effluent gear oil from effluent of lube oil blending plants as an alternative means of mitigating its threats on the environment. Nano lubricant are used in gearboxes for better thermal, friction and anti-wear properties. This is due to the small size and high specific surface area to volume ratio of the nanoparticles. Furthermore, due to their excellent mechanical and thermal properties, easy dispersal in most fluids, inexpensiveness, ease of manufacture, and aspect ratio, the Al2O3 nanoparticles are recently being used by researchers as an additive in gear oils to improve tribological properties, increase power efficiency, extend equipment lifetimes, and lower operating cost. In this work, the alumina nanoparticle was synthesized using co-precipitation method, after which it was characterized using Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD) analysers. After the development of Al2O3-based gear oil from the effluent, the physicochemical and tribological properties of the alumina-based effluent gear oil samples were investigated with varied weight percentages of Al2O3 nanoparticles. The Differential Scanning Calorimetry (DSC) and Computational Fluid Dynamics (CFD) thermal analyses of nano alumina-based gear sample was investigated after obtaining the suitable sample among the sample blends developed. The dispersion of the nanoparticle in the effluent oil improved the specific gravity and pour point whereas a slight reduction was observed in kinematic viscosity at 100 °C, viscosity index and flash point. However, viscosity index and flash point values are conforming to the minimum requirements of API EP 85W90 and ISO 100 standard values. The anti-wear property was observed to significantly improved by 26.14%, at 0.4 wt% nanoparticles concentration. The results showed that, the pure effluent oil recovered is more thermally stable than the 0.4 wt% nano alumina-based effluent gear oil sample, whereas the nano gear oil sample has a higher thermo-oxidative stability than the pure effluent oil. Finally, temperature profiles from the simulation results also ensured a better performance of the 0.4 wt% alumina-based effluent gear oil developed, at 1500 rpm speed of rotation by 6.7% and 8.9% and at 4000 rpm is by 5.9% and 7.8% than the API EP 85W90 and pure effluent oil samples respectively. Hence, based on the results obtained, the study indicated that the effluent oil from lube oil blending plants can be used as gear oil with the dispersion of alumina nanoparticles.

Impact of various parameters on the tribological performance of nano lubricants considering oxide nanoparticles in conventional, semi-synthetic, and fully synthetic lube oils

In the realm of lubrication, nanoparticles exert a notably positive influence on enhancing tribological performance, particularly certain oxide nanoparticles exhibit exceptional capabilities as friction and wear mitigators. However, a substantial research gap exists concerning the efficacy of oxide nanoparticles across various lubricant categories. Therefore, this study meticulously elucidates the effective integration of oxide nanoparticles in diverse lubricant categories. Using HRTEM, XRD, and FTIR, we characterize shape, size, and crystallinity. A Taguchi L18 orthogonal array is used for experimental planning, with performance characteristics of nano lubricants measured using four-ball testers. The experimental findings reveal a hierarchy of parameters governing the minimization of the coefficient of friction (COF), which are as follows: nanoparticle type, nanoparticle composition, load, speed, and lubricant, in that order. Similarly, the parameters controlling the reduction of wear scar diameter (WSD) are ranked as follows: load, nanoparticle composition, nanoparticle type, speed, and lubricant (base oil). Furthermore, an analysis of variance (ANOVA) is conducted to assess the contributions of these factors to COF and WSD. Regarding COF, 43.37% of the variance is attributed to nanoparticle type, 26.78% to nanoparticle composition, 14.49% to load, 11.8% to speed, and 2.36% to lubricant (base oil). In the case of WSD, the factor contributions are 47.67% for load, 22.4% for nanoparticle composition, 14.03% for nanoparticle type, 7.26% for lubricant (base oil), and 7.01% for speed.

Experimental Investigations on Thermophysical, Tribological and Rheological Properties of MoS2 and WS2 Based Nanolubricants with Castor Oil as Base Lubricant

Molybdenum disulfide (MoS2) and Tungsten disulfide (WS2) nanoparticles addition to castor oil produce nano lubricants of novel properties. These nanomaterial additives are dispersed thoroughly in the liquid phase and are intended to boost the base fluid's thermo-physical, rheological, and tribological properties. All these properties have been studied by varying concentrations of nanoparticles from 0.05 to 2.5%. The size of both nanoparticles are in the range of <20nm. The density of nano lubricants was found to change with respect to nanoparticle concentration and temperature. The density increases from 0.06 to 0.6% with respect to the increase in concentration and decreases by 4%, for increasing temperature from 25 to 100 o C. A significant (15 %) increase in thermal conductivity with MoS2 nanoparticles in lubricants could be observed while with WS2 nanoparticles only 8 % enhancement was observed. The rheological study suggests that nano lubricants have better dynamic viscosity and shear stress than neat castor oil. A tribology study showed improved lubrication properties of the nanolubricants as compared with base castor oil. The addition of MoS2 and WS2 nanoparticles in castor oil decreased the friction coefficient by 53 % and 42 %, respectively, and reduced the wear scar diameter by 24% and 20 %, respectively, as compared to base castor oil. This study was done to develop nonedible vegetable oil based nanolubricants exploring their potential as emerging lubricants.