The Secondary Lubrication Effect under Fluid Lubrication

2021 ◽  
Author(s):  
Dinghuai Yang ◽  
Junjie Zhang
Keyword(s):  
Lubrication Effect

scholarly journals Wear Resistance Improvement of Cemented Tungsten Carbide Deep-Hole Drills after Ion Implantation

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 239
Author(s):  
Dmitrij Morozow ◽  
Marek Barlak ◽  
Zbigniew Werner ◽  
Marcin Pisarek ◽  
Piotr Konarski ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Tungsten Carbide ◽  
Photoelectron Spectroscopy ◽  
Secondary Ion Mass Spectrometry ◽  
Carbon Layer ◽  
Hole Drilling ◽  
Deep Hole ◽  
Tungsten Nitrides ◽  
Lubrication Effect ◽  
Secondary Ion

The paper is dedicated to the lifetime prolongation of the tools designed for deep-hole drilling. Among available methods, an ion implantation process was used to improve the durability of tungsten carbide (WC)-Co guide pads. Nitrogen fluencies of 3 × 1017 cm−2, 4 × 1017 cm−2 and 5 × 1017 cm−2 were applied, and scanning electron microscope (SEM) observations, energy dispersive spectroscopy (EDS) analyses, X-ray photoelectron spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS) measurements were performed for both nonimplanted and implanted tools. The durability tests of nonimplanted and the modified tools were performed in industrial conditions. The durability of implanted guide pads was above 2.5 times more than nonimplanted ones in the best case, presumably due to the presence of a carbon-rich layer and extremely hard tungsten nitrides. The achieved effect may be attributed to the dissociation of tungsten carbide phase and to the lubrication effect. The latter was due to the presence of pure carbon layer with a thickness of a few dozen nanometers. Notably, this layer was formed at a temperature of 200 °C, much smaller than in previously reported research, which makes the findings even more valuable from economic and environmental perspectives.

Analysis of Traction Characteristics of Grease-Lubricated Sliding Bearing

2013 ◽  
Vol 655-657 ◽  
pp. 640-643
Author(s):  
Bo Yuan Yang ◽  
Xiaofan Yan ◽  
Bing Su
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Room Temperature ◽  
Extreme Pressure ◽  
Test Rig ◽  
Sliding Bearing ◽  
Traction Coefficient ◽  
Lubrication Effect ◽  
Lubricated Sliding

Adopting the test rig of traction characteristics of grease-lubricated sliding bearing, the practical condition of sliding bearing was simulated and the traction coefficient of DGG Grease under different temperature, velocity and load was tested. Besides, the traction characteristics of the grease were also elaborated. The results indicate that the traction coefficient increases when the temperature gradually rises from room temperature while it gradually decreases when the temperature exceeds 85°C. Under the condition of high temperature and high pressure, the extreme pressure additive has obvious effects, the traction coefficient reducing and maintaining constant, so a better lubrication effect is realized.

Understanding the synergistic lubrication effect of 2-mercaptobenzothiazolate based ionic liquids and Mo nanoparticles as hybrid additives

2018 ◽  
Vol 125 ◽  
pp. 39-45 ◽  
Author(s):  
Yi Li ◽  
Songwei Zhang ◽  
Qi Ding ◽  
Hua Li ◽  
Baofeng Qin ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Lubrication Effect

Tribological Study of Ecological Lubricants Containing Titanium Dioxide Nanoparticles

2014 ◽  
Vol 658 ◽  
pp. 323-328 ◽  
Author(s):  
Filip Ilie ◽  
Cristina Covaliu ◽  
Georgiana Chisiu
Keyword(s):  
Titanium Dioxide ◽  
Tribological Properties ◽  
Titanium Dioxide Nanoparticles ◽  
Load Capacity ◽  
Surface Film ◽  
Protective Film ◽  
Sem Images ◽  
Base Oil ◽  
Two Samples ◽  
Lubrication Effect

Titanium dioxide (TiO2), belonging to the family of transition metal dichalcogenides (together with molybdenum disulfide (MoS2) and tungsten disulphide (WS2)), is well known for its solid lubricating behaviour. Thin films of TiO2 exhibit extremely low coefficient of friction in dry environments, and are typically applied by mixed in oil, grease or impregnated into porous matrix of powdered materials. Current researches in many areas imply the using of different types of nanoparticles in the composition of oily lubricants. Results of these researches upon the friction couples show that nanoparticles contained by lubricant can improve the tribological properties, the friction-wear reduction and the lubrication effect. When nanomaterials are used to improve lubrication effect, the selection of metal is very important. In this paper, the authors chose for investigating the tribological properties of two samples of TiO2 with the mean diameter of 15 nm (n-TiO2) and 250 nm (m-TiO2), under different friction conditions. The tribological properties of TiO2 nanoparticles mixed in the ecological lubricant oil were investigated using a four-ball tribometer and a block-on-ring tribometer and show the lowering of the friction coefficient in comparison to the lubricant base oil. The finally obtained lubricant is not considered toxic for the environment. The analyses of surface film composition, characterized with the help of X-ray photoelectron spectroscope (XPS) and scanning electron microscopy (SEM) images showed that the deposed nanoparticles form a protective film (TiO3) allowing for an increase in the load capacity of friction couple. XPS and SEM were used to examine the morphology of the wear track, after the four-ball experiment. The main advantage of the nanoparticles is ascribed to the release and furnishing of the nanoparticles from the valley onto the friction metal surface and their confinement at the interface. The TiO2 nanoparticles showed lower frictions coefficient and higher wear resistance as compared to the common TiO2 particles (about 1.5 μm in diameter(c- TiO2)) on a four-ball machine, which were caused by the microstructure of the protective film and serve as perfect intermediate lubricants between the contact surfaces.

Study on Mechanism of Separate Type Boundary Lubrication in Low Frequency Torsional Vibration Tapping

2012 ◽  
Vol 424-425 ◽  
pp. 111-114
Author(s):  
Feng Qi Han ◽  
Zhi Zun Li ◽  
De Yuan Zhang
Keyword(s):  
Boundary Lubrication ◽  
Torsional Vibration ◽  
Low Frequency ◽  
Cutting Fluid ◽  
Separate Type ◽  
Cutting Angle ◽  
Lubrication Mode ◽  
Type Boundary ◽  
Lubrication Effect ◽  
Key Parameter

Low frequency torsional vibration tapping is an effective method to solve the problem of tapping in difficult to cut materials. Tapping parameters affect tapping torque and service life of tap, and cutting angle is the key parameter. Experiments were conducted to study the lubrication mechanism and the influence of cutting angle on lubrication effect. Experimental results indicate that the separate type boundary lubrication mode greatly enhances the lubrication effect of cutting fluid and the lubrication effect decreases with the increase of cutting angle. To obtain good technological effect, the smaller cutting angle should be selected.

Enhanced lubrication effect of gallium-based liquid metal with laser textured surface

2019 ◽  
Vol 129 ◽  
pp. 407-415 ◽  
Author(s):  
Xing Li ◽  
Yihong Li ◽  
Zhe Tong ◽  
Qiang Ma ◽  
Yuquan Ni ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Textured Surface ◽  
Lubrication Effect

scholarly journals Tunable viscosity modification with diluted particles: when particles decrease the viscosity of complex fluids

2019 ◽  
Vol 297 (11-12) ◽  
pp. 1507-1517 ◽  
Author(s):  
Manuchar Gvaramia ◽  
Gaetano Mangiapia ◽  
Vitaliy Pipich ◽  
Marie-Sousai Appavou ◽  
Sebastian Jaksch ◽  
...  
Keyword(s):  
Complex Fluids ◽  
Stage Structure ◽  
Solid Particles ◽  
Viscosity Reduction ◽  
Spherical Particles ◽  
Steady Increase ◽  
Two Stage ◽  
Apparent Contradiction ◽  
Domain Structures ◽  
Lubrication Effect

Abstract While spherical particles are the most studied viscosity modifiers, they are well known only to increase viscosities, in particular at low concentrations of approx. 1%. Extended studies and theories on non-spherical particles in simple fluids find a more complicated behavior, but still a steady increase with increasing concentration. Involving platelets in combination with complex fluids—in our case, a bicontinuous microemulsion—displays an even more complex scenario that we analyze experimentally and theoretically as a function of platelet diameter using small angle neutron scattering, rheology, and the theory of the lubrication effect, to find the underlying concepts. The clay particles effectively form membranes in the medium that itself may have lamellar aligned domains and surfactant films in the case of the microemulsion. The two-stage structure of clay and surfactant membranes explains the findings using the theory of the lubrication effect. This confirms that layered domain structures serve for lowest viscosities. Starting from these findings and transferring the condition for low viscosities to other complex fluids, namely crude oils, even lowered viscosities with respect to the pure crude oil were observed. This strengthens our belief that also here layered domains are formed as well. This apparent contradiction of a viscosity reduction by solid particles could lead to a wider range of applications where low viscosities are desired. The same concepts of two-stage layered structures also explain the observed conditions for extremely enhanced viscosities at particle concentrations of 1% that may be interesting for the food industry.

Hydrodynamic Lubrication in Rolling of Thin Strips

1972 ◽  
Vol 94 (1) ◽  
pp. 317-328 ◽  
Author(s):  
B. Avitzur ◽  
G. Grossman
Keyword(s):  
Dimensionless Parameter ◽  
Hydrodynamic Lubrication ◽  
Strip Thickness ◽  
Thin Strip ◽  
Strip Rolling ◽  
Roll Velocity ◽  
The Subject ◽  
Hydrodynamic Effects ◽  
Lubrication Effect ◽  
Lubricant Viscosity

The process of thin strip rolling is analyzed considering the hydrodynamic lubrication effect. Hydrodynamic lubrication prevails when a film of lubricant fully separates the rolls from the strip. The conditions which produce hydrodynamic effects are the subject of this study. A dimensionless parameter, the Sommerfeld Number, is defined as a function of lubricant viscosity, roll velocity, strip thickness, and yield strength of the material. The critical Sommerfeld Number for occurrence of hydrodynamic lubrication is determined. Increasing lubricant viscosity and roll velocity or decreasing flow stress and strip thickness produce a larger Sommerfeld Number with an increased tendency for hydrodynamic effects. The thickness of the lubricant film and the velocity of the emerging strip are both determined as functions of the Sommerfeld Number, reduction in strip thickness, and of roll diameter. Graphical and numerical examples are presented.

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