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.

Tribological Properties of Nano-Sized Molybdenum Disulfide Particles

2005 ◽  
Author(s):  
Xianguo Hu ◽  
Yucheng Wu ◽  
Guangcheng Yuan ◽  
Peng Huang ◽  
Hefeng Jing
Keyword(s):  
Friction Coefficient ◽  
Metal Surface ◽  
Tribological Properties ◽  
Surface Composition ◽  
Load Capacity ◽  
Nano Particles ◽  
Lubricating Oil ◽  
Protective Film ◽  
Extreme Pressure ◽  
Sem Images

This paper summarizes the tribological properties of MoS2 nano-particles with about 30 nm under different frictional conditions. By four-ball tribometer, the results showed that as the nano-MoS2 content is over 0.5 wt% the extreme pressure of lubricating oil is higher than to 30% than that of lubricating oil with same content of common MoS2. The nano-MoS2 particles can decrease the friction coefficient of lubricating oil obviously. However the results showed that their friction reductions have not obvious difference by the ring-on-block tribometer. The analyses of surface composition conducted by XPS and SEM images showed that the nanoparticles form a protective film (WO3) allowing an increase in the load capacity of rubbed pairs. The main advantage of the nanoparticles is ascribed to the release and furnishing of the nanoparticles from the valley onto the rubbing metal surface and their confinement at the interface.

scholarly journals Preparation and Tribological Properties of Carbon-Coated WS2 Nanosheets

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2835 ◽  
Author(s):  
Zheng Li ◽  
Fanshan Meng ◽  
Haohao Ding ◽  
Wenjian Wang ◽  
Qiyue Liu
Keyword(s):  
Tribological Properties ◽  
Friction And Wear ◽  
Hydrothermal Reaction ◽  
Matrix Material ◽  
Lubricant Additive ◽  
Wear Scar ◽  
Protective Film ◽  
Wear Scar Diameter ◽  
Base Oil ◽  
Carbon Coated

WS2-C is produced from a hydrothermal reaction, in which WS2 nano-sheets are coated with carbon, using glucose as the carbon source. In order to investigate the tribological properties of WS2-C as a lubricant additive, WS2-C was modified by surfactant Span80, and friction tests were carried out on an MRS-10A four-ball friction and wear tester. The results show that Span80 can promote the dispersibility of WS2-C effectively in base oil. Adding an appropriate concentration of WS2-C can improve the anti-wear and anti-friction performance of the base oil. The friction coefficient reached its lowest point upon adding 0.1 wt % WS2-C, reduced by 16.7% compared to the base oil. Meanwhile, the wear scar diameter reached its minimum with 0.15 wt % WS2, decreasing by 26.45%. Moreover, at this concentration, the depth and width of the groove and the surface roughness on the wear scar achieved their minimum. It is concluded that WS2-C dispersed in oil could enter friction pairs to avoid their direct contact, thereby effectively reducing friction and wear. At the same time, WS2-C reacts with the friction matrix material to form a protective film, composed of C, Fe2O3, FeSO4, WO3, and WS2, repairing the worn surface.

scholarly journals Improvement of Hydrophilicity for Polyamide Composite Membrane by Incorporation of Graphene Oxide-Titanium Dioxide Nanoparticles

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Thu Hong Anh Ngo ◽  
Chau Thi Minh Nguyen ◽  
Khai Dinh Do ◽  
Quan Xuan Duong ◽  
Nghia Hieu Tran ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Graphene Oxide ◽  
Membrane Separation ◽  
Titanium Dioxide Nanoparticles ◽  
Membrane Surface ◽  
Separation Performance ◽  
Sem Images ◽  
Antifouling Property ◽  
Coated Membranes ◽  
Atr Spectroscopy

In this work, the polyamide (PA) membrane surface has been modified by coating of nanomaterials including graphene oxide (GO) and titanium dioxide (TiO2) to enhance membrane separation and antifouling properties. The influence of surface modification conditions on membrane characteristics has been investigated and compared with a base membrane. Membrane surface properties were determined through scanning electron microscope (SEM) images and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. Membrane separation performance was determined through the possibility for the removal of methylene blue (MB) in water. Membrane antifouling property was evaluated by the maintained flux ratios (%) after 120 minutes of filtration. The experimental results showed that the appearance of hydrophilic groups after coating of GO and TiO2 nanocomposite materials with or without UV irradiation onto membrane surface made an improvement in the separation property of the coated membranes. The membrane flux increased from 28% to 61%; meanwhile, the antifouling property of the coated membranes was improved clearly, especially for UV-irradiated PA/GO-TiO2 membrane.

scholarly journals Salt Stress Mitigation via the Foliar Application of Chitosan-Functionalized Selenium and Anatase Titanium Dioxide Nanoparticles in Stevia (Stevia rebaudiana Bertoni)

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4090
Author(s):  
Morteza Sheikhalipour ◽  
Behrooz Esmaielpour ◽  
Gholamreza Gohari ◽  
Maryam Haghighi ◽  
Hessam Jafari ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Salt Stress ◽  
Titanium Dioxide Nanoparticles ◽  
Chitosan Nanoparticles ◽  
Stevia Rebaudiana ◽  
High Salt ◽  
Steviol Glycosides ◽  
Rebaudioside A ◽  
Tio2 Nps ◽  
Stevia Rebaudiana Bertoni

High salt levels are one of the significant and major limiting factors on crop yield and productivity. Out of the available attempts made against high salt levels, engineered nanoparticles (NPs) have been widely employed and considered as effective strategies in this regard. Of these NPs, titanium dioxide nanoparticles (TiO2 NPs) and selenium functionalized using chitosan nanoparticles (Cs–Se NPs) were applied for a quite number of plants, but their potential roles for alleviating the adverse effects of salinity on stevia remains unclear. Stevia (Stevia rebaudiana Bertoni) is one of the reputed medicinal plants due to their diterpenoid steviol glycosides (stevioside and rebaudioside A). For this reason, the current study was designed to investigate the potential of TiO2 NPs (0, 100 and 200 mg L−1) and Cs–Se NPs (0, 10 and 20 mg L−1) to alleviate salt stress (0, 50 and 100 mM NaCl) in stevia. The findings of the study revealed that salinity decreased the growth and photosynthetic traits but resulted in substantial cell damage through increasing H2O2 and MDA content, as well as electrolyte leakage (EL). However, the application of TiO2 NPs (100 mg L−1) and Cs–Se NPs (20 mg L−1) increased the growth, photosynthetic performance and activity of antioxidant enzymes, and decreased the contents of H2O2, MDA and EL under the saline conditions. In addition to the enhanced growth and physiological performance of the plant, the essential oil content was also increased with the treatments of TiO2 (100 mg L−1) and Cs–Se NPs (20 mg L−1). In addition, the tested NPs treatments increased the concentration of stevioside (in the non-saline condition and under salinity stress) and rebaudioside A (under the salinity conditions) in stevia plants. Overall, the current findings suggest that especially 100 mg L−1 TiO2 NPs and 20 mg L−1 Cs–Se could be considered as promising agents in combating high levels of salinity in the case of stevia.

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