Investigation of the Tribological Behavior of Mineral Lubricant Using Copper Oxide Nano Additives

In this study, tribological properties of custom formulated and stabilized nano lubricant are investigated. Spherical CuO nanoparticles are suspended in 20W-50 mineral base lubricant using Oleic Acid (OA) as a surfactant. Three different nano lubricant concentrations with 0.2, 0.5, and 1 wt.% were analyzed through ASTM G-99 pin-on-disc tribometer standardized test under boundary/mixed lubrication regimes. The generated friction and wear analyses confirm a consolidation of tribological properties with a reduction in friction coefficient in the range of 14.59–42.92%, compared with the base lubricant. Analysis of worn surfaces (SEM/EDX) as well as (AFM) was conducted. Combined hypotheses were proposed from the analysis of worn surfaces; these hypotheses suggested that CuO nanoparticles exhibit an integrated effect of two phenomenal lubrication mechanisms. Additionally, dispersion stability evaluation of the suspended nanoparticles was performed through Zeta potential, (FTIR), and sedimentation analyses. Stability results showed that steric stabilization is the dominating effect of the repulsive forces between nanoparticles, surpassing the electrostatic repulsive forces.

Effect of Additivized Biodiesel Blends on Diesel Engine Performance, Emission, Tribological Characteristics, and Lubricant Tribology

This research work focuses on investigating the lubricity and analyzing the engine characteristics of diesel–biodiesel blends with fuel additives (titanium dioxide (TiO2) and dimethyl carbonate (DMC)) and their effect on the tribological properties of a mineral lubricant. A blend of palm–sesame oil was used to produce biodiesel using ultrasound-assisted transesterification. B30 (30% biodiesel + 70% diesel) fuel was selected as the base fuel. The additives used in the current study to prepare ternary fuel blends were TiO2 and DMC. B30 + TiO2 showed a significant reduction of 6.72% in the coefficient of friction (COF) compared to B30. B10 (Malaysian commercial diesel) exhibited very poor lubricity and COF among all tested fuels. Both ternary fuel blends showed a promising reduction in wear rate. All contaminated lubricant samples showed an increment in COF due to the dilution of combustible fuels. Lub + B10 (lubricant + B10) showed the highest increment of 42.29% in COF among all contaminated lubricant samples. B30 + TiO2 showed the maximum reduction (6.76%) in brake-specific fuel consumption (BSFC). B30 + DMC showed the maximum increment (8.01%) in brake thermal efficiency (BTE). B30 + DMC exhibited a considerable decline of 32.09% and 25.4% in CO and HC emissions, respectively. The B30 + TiO2 fuel blend showed better lubricity and a significant improvement in engine characteristics.

Improved biodegradability and tribological performances of mineral lubricating oil by two synthetic nitrogenous heterocyclic additives

Purpose This paper aims to understand the influences of tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester on biodegradability and tribological performances of mineral lubricating oil. Design/methodology/approach Tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester were prepared and characterized by Fourier transform infrared spectrometer. The biodegradability and tribological properties of neat oil and its formulations were studied on a tester for fast evaluating biodegradability of lubricants and a four-ball tester, respectively. The worn surfaces were investigated by scanning electron microscope and X-ray photoelectron spectroscope. Findings Tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester both improved markedly the biodegradability, the anti-wear properties, friction-reducing properties and extreme pressure properties of base oil. The effect of oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester was better than tris (2-hydroxyethyl) isocyanurate oleate. The improvement of tribological performances was mainly ascribed to the formation of a complicated boundary lubrication film of tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester on the friction surfaces. Originality/value This paper has indicated that tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester effectively improve the biodegradability and tribological performances of mineral lubricating oil. Promoting biodegradation of mineral lubricant by additives is very significant for the development of petroleum-based biodegradable lubricants. These two additives not merely improve the tribological performances; more importantly, they improve the ecological performances.

Tribological Investigation of Copper (Cu) and Copper Oxide (CuO) Nanoparticles Based Nanolubricants for Machine Tool Slideways

The present study intends to evaluate the tribological characteristics of Copper (Cu) and Copper oxide (CuO) based nanolubricant for its use in machine tool slideways. Different sizes of copper and copper oxide particles were chosen and physical characterisation were carried out using scanning electron microscope (SEM) and transmission electron microscope (TEM). The nanolubricants were prepared by adding various proportions (0.1%, 0.25%, 0.4% wt) of the particles in Polyalphaolefin (PAO) base oil with lecithin and oleic acid surfactants. Friction and stick-slip characteristics of the nanolubricants were assessed using pin-on-block reciprocating friction monitor simulating the actual loading conditions prevailing in machine tool slideways. Studies were also conducted under elevated temperatures to ascertain the performance of particles at higher temperatures. Extreme pressure properties of the lubricants were studied using Four Ball Tester. The results of the experiments were compared with ISO VG 32 oil, a conventional mineral lubricant meant for machine tool slideways and it was found that the tribological properties nanolubricants using both the nanoparticles were considerably better. The coefficient of friction found to be decreased by 2.5% and 17.5% for copper particles with 0.1% weight composition in ambient temperature and elevated temperature respectively. Whereas for copper oxide particles with 0.1% weight composition a reduction of 14.25% and 10% were obtained.

Lubricity of Palm Fatty Acid Distillates at Various Rotational Speeds

Lubricant oils play essential role in manufacturing processes for reducing friction and wear between contact parts at different speeds. Palm fatty acid distillate (PFAD) is a new source from vegetable oil and has potential as an alternative source of mineral lubricant oils. This study was performed at various speeds (800, 1200, and 1600 rpm) and at a constant load (392N), temperature (75°C), and time (1 h) using a four-ball tribotester. To evaluate the PFAD results, similar experiments were done using hydraulic oil, and the results were compared mutually. The results showed that the anti-friction, anti-wear, viscosity, and flash temperature parameter (FTP) of PFAD were higher than those of hydraulic mineral oil.

The Tribological Characteristic of the Blends of Rbd Palm Olein with Mineral Oil Using Four-ball Tribotester

Vegetable oils are sustainable fluids which have been promoted to replace petroleum-based oils due to its environment friendly characteristics; it is being a very important supply of biolubricant. The excellent advantage of vegetable oil is the fact it is really which can be used environment friendly supplier. In addition, vegetable oil based lubricant clearly show the possibility to minimize carbon monoxide also hydrocarbon emissions when used in IC engines. There are basically two different ways to using vegetable oil to be a bio-lubricant, either one by directly use the pure vegetable oil with additives or use certain blending ratio of vegetable oil with mineral lubricant. In this paper, the influences of the blending ratio of mineral oil with RBD palm olein on the tribological characteristics were investigated and compared with commercial lubricant oil by using the four ball tribotester. The blending ratio was varied from neat with interval of 20% by volume. All experimental works were conforming to ASTM D4172. The results exhibited that the blend of RBD palm olein with commercial lubricant oil has lower the wear scar of ball bearings and coefficient of friction compared to commercial lubricant oil. As a conclusion, the blending of RBD palm olein with commercial lubricant oil has better performance compared to commercial lubricant oil or pure RBD palm olein.

Influence of Dispersant on the Dispersion Stability of Nano-CoFe2O4 Refrigeration Oil

Adding dispersants like surfactants and polymers to modify nanoparticles surface is an effective way to enhance the dispersion stability of nanoparticles in refrigeration oil. In this paper, many groups of nano-CoFe2O4refrigeration oil were prepared. In order to obtain the most effective kind of dispersant and the optimum additive amount, sedimentation observation method was employed for evaluation of the dispersion stability of CoFe2O4nanoparticles in 3GS mineral lubricant. The spectral behavior of the surface modified nano-CoFe2O4was studied by Fourier transform infrared (FT-IR) spectrometer. It was revealed that the optimized mass ratio between nano-CoFe2O4and dispersant ratio is 2 to 5; a relatively appropriate dispersant for nano-CoFe2O4would be Tween40, Tween60, Span80, Span80; Tween60 was the best. It was also illustrated in the infrared spectrum that nano-CoFe2O4particles surface modified by Tween60 was connected by organic groups in Tween60. Thus, the particles changed from hydrophilic to lipophilic and performed good dispersity and high stability when dispersed in mineral refrigeration oil.

Evaluation of the biodegradation of different types of lubricant oils in liquid medium

The aim of this work was to study the biodegradation of different types of automotive lubricant oils adapted to the aqueous medium using a base inoculum and an aqueous inoculum. Four treatments were carried out in two consecutive and similar experiments: T1 (control); T2 (half-synthetic oil); T3 (mineral oil); T4 (used oil). The results showed the following decreasing order of CO2 production in the Bartha and Pramer respirometers: T4 > T2 > T3 > T1. Thus, the used lubricant oil showed with highest biodegradability, followed by the half-synthetic one and the mineral oil. It was also observed that the mineral lubricant presented a longer period of adaptation compared to the half-synthetic one.