scholarly journals Improving the lubrication and anti-corrosion performance of polyurea grease via ingredient optimization

Friction ◽  
2020 ◽  
Author(s):  
Guanlin Ren ◽  
Xiaowen Sun ◽  
Wen Li ◽  
Hao Li ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Performance Characteristics ◽  
Friction Reduction ◽  
Chemical Components ◽  
Load Carrying Capacity ◽  
Wear Properties ◽  
Base Oil ◽  
Lubrication Film ◽  
Load Carrying ◽  
Polyurea Grease ◽  
Organic Amines

Abstract Thickener formulation plays a significant role in the performance characteristics of grease. The polyurea greases (PUGs) were synthesized using mineral oil (500SN) as the base oil, and by regulating the reaction of diphenylmethane diisocyanate (MDI) and different organic amines. The as-prepared PUGs from the reaction of MDI and cyclohexylamine/p-toluidine exhibit the optimum physicochemical and friction-wear properties, confirming that the regulation of thickener formulation can improve the performance characteristics of grease, including friction reduction, wear, corrosion resistance, and load-carrying capacity. The anticorrosion and lubrication properties of as-prepared PUGs depend on good sealing functions and a boundary lubrication film (synergy of grease-film and tribo-chemical reaction film), as well as their chemical components and structure.

scholarly journals Tribology Properties of Synthesized Multiscale Lamellar WS2 and Their Synergistic Effect with Anti-Wear Agent ZDDP

2019 ◽  
Vol 10 (1) ◽  
pp. 115 ◽  
Author(s):  
Na Wu ◽  
Ningning Hu ◽  
Jinhe Wu ◽  
Gongbo Zhou
Keyword(s):  
Friction Coefficient ◽  
Synergistic Effect ◽  
Solid Phase ◽  
Friction Reduction ◽  
Lubricating Oil ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Wear Properties ◽  
Base Oil ◽  
Electron Probe Micro Analyzer

The microscale/nanoscale lamellar-structure WS2 particles with sizes of 2 µm and 500 nm were synthesized by solid-phase reaction method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The synergies between microscale/nanoscale WS2 particles and ZDDP as lubricating oil additives was evaluated by means of UMT-2 tribometer at room temperature. The wear scars were examined with SEM and electron-probe micro-analyzer (EPMA). The results show that the anti-wear properties were improved and the friction coefficient was greatly decreased with the simultaneous addition of WS2 particles and ZDDP, and the largest reduction of friction coefficient was 47.2% compared with that in base oil. Moreover, the presence of ZDDP additive in the lubricant further enhances the friction-reduction and anti-wear effect of microscale/nanoscale WS2. This confirms that there is a synergistic effect between WS2 particles and ZDDP.

Tribological Investigation of Nanographite Platelets as Additive in Anti-Wear Lubricant: A Top-Down Approach

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Flavio A. C. Vidal ◽  
Antonio F. Ávila
Keyword(s):  
Friction Coefficient ◽  
Friction Reduction ◽  
Wear Properties ◽  
Top Down ◽  
Base Oil ◽  
Graphene Layers ◽  
Sliding Mechanism ◽  
Wear And Friction ◽  
Different Types ◽  
Mineral Base

A top-down approach is employed to investigate the tribological effect of adding nanographite platelets (NGPs) to mineral base oil (MBO). The performance of the NGP-modified MBO was evaluated by examining the friction and anti-wear properties. Four different types of NGPs produced by two different processes were employed. The optimal NGP-modified MBO attained a significant wear and friction reduction when compared with the MBO without NGPs. The process used to exfoliate the graphite nanoplatelet samples provided better wear properties because of the graphene layers' smoother sliding mechanism. Graphene layers seeped inside the groove marks to keep the friction coefficient low.

scholarly journals Nanoparticles of Zn and ZnO as extreme pressure (EP) additives for lubricants

2018 ◽  
Vol 16 (5) ◽  
Author(s):  
Jose Taha Tijerina ◽  
Flavio Castillo ◽  
Javier Leal ◽  
Laura Peña Parás ◽  
Demófilo Maldonado Cortés ◽  
...  
Keyword(s):  
Automotive Industry ◽  
Metal Forming ◽  
Critical Issue ◽  
Measuring System ◽  
Zno Nanoparticle ◽  
Load Carrying Capacity ◽  
Extreme Pressure ◽  
Wear Properties ◽  
Load Carrying ◽  
Nanoparticle Additives

The tribological behavior of moving components and tooling in the automotive industry is a critical issue for improving tool life and increasing efficiency. This work discusses the effects of Zn and ZnO nanoparticle additives homogeneously dispersed within a metal-forming synthetic fluid at various filler fractions: 0.01, 0.05 and 0.10wt.%. Nanolubricants were evaluated under scuffing conditions at extreme pressures (EP) conditions using a four-ball tribotester in order to obtain the load-carrying capacity (poz) behavior, and overall tribological characteristics. This method has shown, with great precision, the influence of the nanofillers on the EP behavior of conventional lubricants. Worn surfaces were characterized through Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) to determine the tribological mechanisms of nanoparticles. An Alicona 3D surface measuring system was used for measuring the surface roughness of the wear scars. Both nanoparticles exhibited better friction-reducing and anti-wear properties compared to the base synthetic fluid. For Zn-based nanolubricants, an enhancement of ~180% in poz was obtained with 0.10wt.%, showing the effect of the spherical nanostructures that were tribosintered onto the surface due to the EPs of the test. Furthermore, the highest enhancement in poz (up to 250%) was achieved with incorporation of 0.10wt.% of ZnO demonstrating the potential of nanolubricants for improving the efficiency of mechanical components.

scholarly journals Combined Effect of Slip Velocity and Surface Roughness on a Magnetic Squeeze Film for a Sphere in a Spherical Seat

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
G. M. Deheri ◽  
Sejal J. Patel
Keyword(s):  
Surface Roughness ◽  
Slip Velocity ◽  
Type Equation ◽  
Velocity Slip ◽  
Performance Characteristics ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Slip Model ◽  
Load Carrying ◽  
Effect Of Surface

This investigation analyzes the performance of a magnetic fluid based squeeze film for a sphere in a rough spherical seat with slip velocity. The slip model of Beavers and Joseph has been deployed to study the effect of velocity slip while the stochastic model of Christensen and Tonder has been used to calculate the effect of surface roughness. The concerned statistically averaged Reynolds’ type equation is solved to derive the pressure distribution which results in the calculation of load carrying capacity. The results presented in graphical forms confirm that the adverse effect of slip velocity can be overcome to a large extent at least in the case of negatively skewed roughness. However, lower values of slip may be preferred for enhancing the performance characteristics of the bearing system. Besides, variance (−ve) provides a little support to improve the performance characteristics.

Performance characteristics of rectangular aerostatic thrust bearing by conformal mapping

2018 ◽  
Vol 70 (8) ◽  
pp. 1457-1475
Author(s):  
Shang-Han Gao ◽  
Sheng-Long Nong
Keyword(s):  
Conformal Mapping ◽  
Pressure Distribution ◽  
Carrying Capacity ◽  
Thrust Bearing ◽  
Performance Characteristics ◽  
Load Carrying Capacity ◽  
Möbius Transform ◽  
Content Type ◽  
Air Supply ◽  
Load Carrying

Purpose This paper aims to analyze the pressure distribution of rectangular aerostatic thrust bearing with a single air supply inlet using the complex potential theory and conformal mapping. Design/methodology/approach The Möbius transform is used to map the interior of a rectangle onto the interior of a unit circle, from which the pressure distribution and load carrying capacity are obtained. The calculation results are verified by finite difference method. Findings The constructed Möbius formula is very effective for the performance characteristics researches for the rectangular thrust bearing with a single air supply inlet. In addition, it is also noted that to obtain the optimized load carrying capacity, the square thrust bearing can be adopted. Originality/value The Möbius transform is found suitable to describe the pressure distribution of the rectangular thrust bearing with a single air supply inlet.

scholarly journals Evaluation of Load Carrying Capacity of Hydrodynamic Journal Bearing with Nanolubricants

10.29007/pq98 ◽  
2018 ◽  
Author(s):  
Tushar Gundarneeya ◽  
Dipak Vakharia
Keyword(s):  
Carrying Capacity ◽  
Journal Bearing ◽  
Volume Fraction ◽  
Classical Model ◽  
Viscosity Model ◽  
Load Carrying Capacity ◽  
Base Oil ◽  
Lubricant Oil ◽  
Load Carrying ◽  
Hydrodynamic Journal Bearing

In this work, influence of nanolubricants on the load carrying capacity of hydrodynamic journal bearing is studied. Increase in viscosity of lubricant oil with nanopartical as lubricant additives is modeled using different classical model and compared with Kriger-Doughetry viscosity model. This Kriger-Doughetry viscosity model for simulating viscosity of nanolubricant is validated by Experimental verification using reheometer. The pressure distribution and load carrying capacity are theoretically analyzed using Reynolds Equation for Reynolds boundary condition for different concentration of nanoparticles volume fraction. Result reveal increase in pressure and load carrying capacity of Journal bearing with nanolubricants in comparison to base oil.

scholarly journals Comparative study on corrosion resistance and lubrication function of lithium complex grease and polyurea grease

Friction ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 75-91
Author(s):  
Guanlin Ren ◽  
Pengfei Zhang ◽  
Xiangyuan Ye ◽  
Wen Li ◽  
Xiaoqiang Fan ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Salt Spray ◽  
Friction Reduction ◽  
Component Structure ◽  
Base Oil ◽  
Lithium Complex ◽  
Polyurea Thickener ◽  
Polyurea Grease ◽  
Lithium Complex Grease

AbstractIn this study, lithium complex grease (LCG) and polyurea grease (PUG) were synthesized using mineral oil (500SN) and polyalphaolefin (PAO40) as base oil, adsorbed onto lithium complex soap and polyurea as thickeners, respectively. The effects of grease formulation (thickener and base oil with different amounts (80, 85, and 90 wt%) on the corrosion resistance and lubrication function were investigated in detail. The results have verified that the as-prepared greases have good anti-corrosion ability, ascribed to good salt-spray resistance and sealing function. Furthermore, the increase in the amount of base oil reduces the friction of the contact interface to some extent, whereas the wear resistance of these greases is not consistent with the friction reduction, because the thickener has a significant influence on the tribological property of greases, especially load-carrying capacity. PUG displays better physicochemical performance and lubrication function than LCG under the same conditions, mainly depending on the component/structure of polyurea thickener. The polyurea grease with 90 wt% PAO displays the best wear resistance owing to the synergistic lubrication of grease-film and tribochemical film, composed of Fe2O3, FeO(OH), and nitrogen oxide.

scholarly journals Impact of Fuel Contents on Tribological Performance of PAO Base Oil and ZDDP

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 79 ◽  
Author(s):  
Yan Zhou ◽  
Weimin Li ◽  
Benjamin Stump ◽  
Raynella Connatser ◽  
Sladjan Lazarevic ◽  
...  
Keyword(s):  
Wear Rate ◽  
Carrying Capacity ◽  
Acid Number ◽  
Load Carrying Capacity ◽  
Oil Viscosity ◽  
Total Acid ◽  
Base Oil ◽  
Fuel Concentration ◽  
Load Carrying ◽  
The Impact

Fuel and water contents are inevitable in automotive engine oils. This study intends to investigate the impact of the addition of gasoline (3–20%) and water (1%) on the lubricating performance of synthetic base oil (PAO), with or without an anti-wear additive (ZDDP), for a steel-cast iron contact. Fuel-added PAO showed an increase in the load carrying capacity. Oil electrical conductivity and total acid number (TAN) measurements showed slightly increased conductivity and marginally increased acidity at a higher fuel concentration. In contrast, an increased wear rate, proportional to the fuel concentration, was observed in a prolonged test with constant-loading. Results suggested that the fuel addition is a double-edged sword: reducing the scuffing risk by providing stronger surface adsorption and increasing the sliding wear rate by bringing down the oil viscosity. The PAO-water blend formed an emulsion and resulted in a significantly increased load-carrying capacity, again likely due to the higher polarity and possibly acidity. For the ZDDP-containing PAO, the addition of 1% water and 3% fuel generated 24% and 52% higher wear. The phosphate polymerization level was reduced on the worn surfaces by the introduction of water but the thickness of ZDDP tribofilm was not significantly affected.

Synthesis and Tribological Behaviors of SiO2/SnO2 Composite Nanoparticles in Rapeseed Oil

2015 ◽  
Vol 713-715 ◽  
pp. 2928-2932 ◽  
Author(s):  
Jian Hua Fang ◽  
Bo Shui Chen ◽  
Xue Chun Wang ◽  
Jiu Wang ◽  
Jiang Wu
Keyword(s):  
Carrying Capacity ◽  
Rapeseed Oil ◽  
Chemical Species ◽  
Load Carrying Capacity ◽  
Subsequent Formation ◽  
Base Oil ◽  
X Ray ◽  
Lubricating Layer ◽  
Load Carrying ◽  
Shearing Strength

SiO2/SnO2-complex nanoparticles were prepared making use of a chemical method. The tribological properties of the resulting complex nanoparticles as an additive in rapeseed oil were evaluated using four–ball friction testers. The topographies and the chemical species of the worn surfaces of steel ball were analyzed by a scanning electron microscope (SEM) and an X-ray photoelectron spectroscope (XPS), respectively. It was found that the complex nanoparticles as the additive contributed to greatly improve the anti-wear ability and load-carrying capacity of the rapeseed base oil. The improved anti-wear ability and load-carrying capacity of the base stock in the presence of the complex nanoparticles as the additive were attribute to the adsorption and deposition of the nanoparticles on the sliding surface and subsequent formation of a boundary lubricating layer with a small shearing strength.

Influence of Geometry and Deformation on the Performance of Profiled Hydrosatic Thrust Bearings

2003 ◽  
Author(s):  
Jianpeng Feng ◽  
Harish Cherukuri ◽  
Robert E. Johnson ◽  
Noah Manring
Keyword(s):  
Contact Area ◽  
Thrust Bearing ◽  
Load Carrying Capacity ◽  
Ball Joint ◽  
Thrust Bearings ◽  
Lubrication Film ◽  
Deforma Tion ◽  
Standard Design ◽  
Load Carrying ◽  
The Impact

In a previous study, the authors investigated the effect of various thrust bearing profiles on the bearing performance and concluded that bearing performance is significantly influenced by the deformations resulting from lubrication film pressure. In the present work, results from a recent study on the effect of the interaction between the ball-joint and bearing on bearing deforma tion and hence, on bearing performance are reported. The motivation behind the study is to investigate the impact of raising or lowering the contact area between the ball-joint and bearing surface on bearing performance as this has the effect of influenceing the bearing deformation. Several designs involving various geometries of the bearing that affect the contact area are considered. The coupled fluid-solids problem is solved by using an iterative technique where the fluid problem is solved using the lubrication theory and the bearing deformation is analyzed by using the commercial FEA software ABAQUS standard. Results from the numerical simulations are compared with experimental results for the standard design of the bearing. The effect of varying the pocket width on the load carrying capacity of the bearing is also investigated.

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