Ultra-low wear and anti-oxidation properties of microcrystalline graphite oxide-magnesium silicate hydroxide composite nanoadditives in the poly-alpha-olefin base oil

2021 ◽  
pp. 1-23
Author(s):  
Wang Kai ◽  
Qiuying Chang ◽  
Rongqin Gao
Keyword(s):  
Graphite Oxide ◽  
Photoelectron Spectroscopy ◽  
Hydrothermal Process ◽  
Magnesium Silicate ◽  
Wear Scar ◽  
Wear Properties ◽  
Wear Scar Diameter ◽  
Base Oil ◽  
X Ray ◽  
Alpha Olefin

Abstract Graphite-based materials and hydrothermal synthetic magnesium silicate hydroxide (MSH) had shown outstanding performances as lubricant additives. In this paper, microcrystalline graphite oxide-magnesium silicate hydroxide (MGO-MSH) composite additives using pre-oxidized MGO as one of the precursors were prepared at a mild hydration condition, and their tribological properties in poly-alpha-olefin oil (PAO 10) were demonstrated by a four-ball tester. The tribological results showed that the optimal concentration of MGO-MSH in oil was 0.3 wt% under 600 N, 600 rpm. Meanwhile, the average wear scar diameter of the ball samples tested in composite-suspending oil was reduced by 36.3% compared with that obtained by pure PAO 10. By means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectra, and X-ray photoelectron spectroscopy (XPS), it was verified that MGO was involved in the synthesis of MSH, and MSH was anchored on MGO during the hydrothermal process. In addition, it was confirmed that carbon-containing tribo-film was formed on the smooth wear region of the wear scar, and was of excellent anti-oxidation wear properties.

scholarly journals Friction Behavior of Silver Perrhenate in Oil as Lubricating Additive for Use at Elevated Temperatures

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2199
Author(s):  
Junhai Wang ◽  
Ting Li ◽  
Tingting Yan ◽  
Xiaoyi Wei ◽  
Xin Qu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Elevated Temperatures ◽  
Synthesis Method ◽  
Chemical Properties ◽  
Solution Synthesis ◽  
Friction Behavior ◽  
Base Oil ◽  
X Ray ◽  
Wide Range ◽  
Alpha Olefin

In this study, we use an aqueous solution synthesis method to prepare silver perrhenate powders and suspend them into a poly alpha olefin (PAO) base oil with polyoxyethylene octylphenyl ether. Four ball tests and ball-on-disk reciprocating mode are performed to determine how silver perrhenate performs tribologically as a lubricating additive over a wide range of temperatures. The physical and chemical properties, as well as the lubricating mechanisms of the silver perrhenate additive, are characterized via X-ray diffraction, scanning electron microscope, Fourier transformation infrared spectroscopy, Raman spectrum, and X-ray photoelectron spectroscopy. The four-ball test results demonstrate that the oil added with silver perrhenate additive is more effective than the base oil in reducing friction and improving wear resistance, and provides the best lubricating performance when at a concentration of 0.5 wt%. The reciprocating mode findings indicate that the hybrid lubricant exhibits distinctively better tribological properties than the base oil at high temperatures, and its low shear strength and chemical inertness allow for low friction at elevated temperatures. The resulting silver perrhenate layer that incorporates native superalloy oxides on the worn surface can provide lubrication by serving as a barrier that prevents direct contact between the rubbing surfaces at elevated temperatures.

scholarly journals Tribological properties of novel palygorskite nanoplatelets used as oil-based lubricant additives

Friction ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 332-343 ◽  
Author(s):  
Kunpeng Wang ◽  
Huaichao Wu ◽  
Hongdong Wang ◽  
Yuhong Liu ◽  
Lv Yang ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Magnesium Silicate ◽  
Treatment Method ◽  
Lubricant Additives ◽  
Wear Volume ◽  
Wear Scar Diameter ◽  
Tribochemical Reaction ◽  
Base Oil ◽  
Transmission Electron ◽  
Ball Surface

AbstractLayered palygorskite (PAL), commonly called attapulgite, is a natural inorganic clay mineral composed of magnesium silicate. In this study, an aqueous miscible organic solvent treatment method is adopted to prepare molybdenum-dotted palygorskite (Amo-PMo) nanoplatelets, which greatly improved the specific surface area of PAL and the dispersion effect in an oil-based lubricant system. Their layered structure and size were confirmed using transmission electron microscopy (TEM) and atomic force microscopy. Following a tribological test lubricated with three additives (PAL, organic molybdenum (SN-Mo), and Amo-PMo), it was found that the sample of 0.5 wt% Amo-PMo exhibited the best tribological properties with a coefficient of friction of 0.09. Moreover, the resulting wear scar diameter and wear volume of the sliding ball surface were 63% and 49.6% of those lubricated with base oil, respectively. Its excellent lubricating performance and self-repairing ability were mainly attributed to the generated MoS2 adsorbed on the contact surfaces during the tribochemical reaction, thereby effectively preventing the direct collision between asperities on sliding solid surfaces. Thus, as-prepared Amo-PMo nanoplatelets show great potential as oil-based lubricant additives, and this study enriches the existing application of PAL in industry.

A Novel Synthesis of CaWO4:Eu3+ Flower Like Microcrystals in Ethanol/Water Mixed System and Characterization

2012 ◽  
Vol 531-532 ◽  
pp. 512-518 ◽  
Author(s):  
Ye Qing Chen ◽  
Joo Hyun Lee ◽  
Sung Wook Park ◽  
Byung Kee Moon ◽  
Byung Chun Choi ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrothermal Process ◽  
Volume Ratio ◽  
Mixed System ◽  
Mixed Solution ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Xrd Patterns

In this paper, we report a successful synthesis of CaWO4:Eu3+ phosphor via an ethanol assisted hydrothermal process. X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM) were used to investigate the growth of the products. The water and ethanol volume ratio is found to have extraordinary effect on the particle size and morphological appearance. Flower like ~ 1µm superstructures can be obtained with mixed solution of w/e of 50/50 at 120 °C hydrothermal sysnthesis for 12 h. High concentration of ethanol in aqueous solution was discovered to have a tendency in limiting the interaction between the small particles for crystallization. Temperature and time experiments were also performed to further investigate the growth mechanism of the ethanol assisted hydrothermal process. The photoluminescence properties of flower like CaWO4:Eu3+ has also been investigated.

scholarly journals A STUDY ON HYDROTHERMAL SYNTHESIS OF METAL–ORGANIC FRAMEWORK MIL-101

2017 ◽  
Vol 126 (1C) ◽  
pp. 21
Author(s):  
Võ Thị Thanh Châu ◽  
Hoàng Văn Đức
Keyword(s):  
Hydrothermal Synthesis ◽  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Hydrothermal Process ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
Transmission Electron ◽  
Metal Organic ◽  
Adsorption Desorption ◽  
Organic Framework

<p>In the present paper, a synthesis of MIL-101 by hydrothermal process was demonstrated. The obtained samples were characterized by powder X-ray diffraction (PXRD), transmission electron microscope (TEM), nitrogen adsorption/desorption isotherms at 77K, X-ray photoelectron spectroscopy (XPS). The results showed that MIL-101 synthesized by optimal conditions exhibited high crystallinity and surface area. The obtained MIL-101 possesses high stability in water and several organic solvents.</p><p><strong>Keywords:</strong> MIL-101, hydrothermal synthesis, metal organic framework-101. </p>

scholarly journals Tribological Properties of a Self-Repairing Material: Functionalized Graphene/montmorillonite Nanosheets Lubricant Additives

2021 ◽  
Author(s):  
Yujunwen Li ◽  
Rui Yang ◽  
Wu Lei ◽  
Qingli Hao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Friction Pair ◽  
Functionalized Graphene ◽  
Test Results ◽  
Wear Scar Diameter ◽  
Green Method ◽  
X Ray ◽  
Lubricant Property ◽  
Weak Interlayer ◽  
Worn Surface

Abstract The functionalized graphene/montmorillonite (FG/MTT) nanosheets were synthesized through chemically bonding by a simple, green method, which has remarkable dispersion stability in oil and its lubricating performance was evaluated by a four-ball tribometer. The test results show that FG/MTT has a preeminent lubricant property when the concentration is 0.4 mg/ml. Compared with the bare oil sample, its average friction coefficient (FC) and wear scar diameter (WSD) decrease by 50.4 % and 13.2 %, respectively. The synergistic effect between FG and MTT was further explored by comparing the lubricant mechanism of the different additives. After synthetically analyzing worn surface by means of scanning electron microscopy and X-ray photoelectron spectroscopy, the lubrication mechanism of the FG/MTT nanocomposite as oil additive is discussed and postulated: The FG/MTT with weak interlayer adhesion is filled between the friction pairs to avoid contact and clinging of some asperities, and the sliding between the layers plays a role in lubrication. Furthermore, FG/MTT will react with the surface of the friction pair to form a repair layer composed of Fe2O3, SiC, SiO2, and aluminosilicate, mending the grinding surface and promoting the hardness after friction.

scholarly journals Examination of lubricity properties of mineral base oil, containing nanoparticles of hexagonal boron nitride, and evaluation of the influence of surfactants on their sedimentation

2020 ◽  
Vol 69 (4) ◽  
pp. 15-41
Author(s):  
Arkadiusz Chodkiewicz ◽  
Tadeusz Kałdoński
Keyword(s):  
Particle Size ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Wear Test ◽  
Solid Particles ◽  
Wear Scar ◽  
Wear Scar Diameter ◽  
Load Curve ◽  
Base Oil ◽  
Mineral Base

The article presents the results of tests on the lubricity properties of SN150 base oil containing hexagonal boron nitride (h-BN) of different granulation. The boron nitride with a particle size below 100 nm and the second one with a particle size below 25 μm were used. The lubricity tests were carried out on a four-ball apparatus. The methodology of these tests was determined on the basis of the normative document PN-EN ISO 20623: 2018-02, which contains the following parameters characterising the lubricity: initial seizure load ISL [N], weld load WL [N], load-wear index LWI [N], mean wear scar diameter MWSD [mm] obtained in a long duration wear test under a specified load; wear-load curve, i.e., the dependence of the mean wear scar diameter on the load, was also performed. Tests were also carried out to check the influence of selected surfactants on the sedimentation process of hexagonal boron nitride in the SN150 mineral base oil. Based on the conducted research and their analysis, it was found that hexagonal boron nitride has a positive effect on the lubricating properties of the base oil; better results were obtained for the boron nano-nitride with a particle size below 100 nm. It was also found that the problem of sedimentation of the solid particles of hexagonal boron nitride was solved by the addition of succinimide dispersant. Keywords: tribology, lubricity, boron nitride, surfactants, sedimentation

scholarly journals Preparation, characterization, and tribological properties of silica-nanoparticle-reinforced B-N-co-doped reduced graphene oxide as a multifunctional additive for enhanced lubrication

Friction ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 239-249 ◽  
Author(s):  
Sang Xiong ◽  
Baosen Zhang ◽  
Shuai Luo ◽  
Hao Wu ◽  
Zhen Zhang
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Tribological Properties ◽  
Silica Nanoparticle ◽  
Wear Scar Diameter ◽  
Multifunctional Additive ◽  
Base Oil ◽  
X Ray ◽  
Reduced Graphene ◽  
Co Doped

AbstractMicrowave-synthesized SiO2-reinforced B-N-co-doped reduced graphene oxide (SiO2-B-N-GO) nanocomposites were characterized by X-ray photon spectroscopy (XPS), X-ray diffraction (XRD), infrared (IR) spectroscopy, and transmission electron microscopy/energy dispersive X-ray (TEM/EDX) analysis. The tribological properties of the SiO2-B-N-GO prepared as anti-wear additives for enhanced lubrication were studied using a four-ball tester. The experiment results indicated that SiO2-B-N-GO exhibits excellent load-carrying, anti-wear, and anti-friction properties in a base oil, especially at the optimal concentration of additives at 0.15 wt%. The wear scar diameter decreased from 0.70 to 0.37 mm and the coefficient of friction was reduced from 0.092 to 0.070, which reductions are attributed to the formation of B-N and graphene layer tribofilms of several tens of nanometers in thickness that prevented direct contact between metals.

scholarly journals Eco-friendly synthesis of VO 2 with stripped pentavalent vanadium solution extracted from vanadium-bearing shale by hydrothermal process in high conversion rate

2019 ◽  
Vol 6 (2) ◽  
pp. 181116 ◽  
Author(s):  
Qian Kang ◽  
Yimin Zhang ◽  
Shenxu Bao ◽  
Guobin Zhang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Conversion Rate ◽  
Hydrothermal Process ◽  
Lithium Ion ◽  
Raw Material ◽  
High Concentration ◽  
X Ray ◽  
Pentavalent Vanadium ◽  
High Conversion Rate

VO 2 (B) has shown excellent cathode performance in lithium batteries and become a hot research topic in recent years. A stripped vanadium solution extracted from vanadium-bearing shale containing a high concentration of vanadium and certain amounts of impurities was used as a vanadium source to synthesize VO 2 (B) by hydrothermal process. The VO 2 conversion rate can reach as high as 99.47% in a reaction time of 8 h, and this is the highest result reported. The crystalline structure and morphology of the synthesized products were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Furthermore, the electrochemical properties of VO 2 (B) in lithium-ion batteries were investigated. The results indicated that the VO 2 (B) has the initial specific discharge capacity of 192.0 mAh g −1 . Stripped vanadium solution is a raw material for producing V 2 O 5 and NH 4 VO 3 , which are indispensable vanadium sources in VO 2 synthesis. Therefore, synthesis of VO 2 via hydrothermal reduction by oxalic acid using stripped vanadium solution extracted from vanadium-bearing shale as a direct vanadium source is an eco-friendly, innovative and efficient method, and will have a great impact on VO 2 synthesis.

Hydrothermal Fabrication of BiVO4/ Diatomite Composite Photocatalysts and their Photocatalytic Performance

2021 ◽  
Vol 904 ◽  
pp. 350-357
Author(s):  
Tian Qing Cui ◽  
Jun Feng Ma ◽  
Qun Si Wang ◽  
Qi Zhou ◽  
Dong Bin Tang
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Photocatalytic Performance ◽  
Hydrothermal Process ◽  
Precursor Solution ◽  
Chelating Agent ◽  
High Porosity ◽  
X Ray ◽  
Composite Photocatalysts ◽  
Vis Spectroscopy

A hydrothermal process was proposed to prepare BiVO4/ diatomite composite photocatalysts, where BiVO4 was grown from a precursor solution containing diatomite, and EDTA used as a chelating agent to prevent the precipitation of precursor solution compositions on diatomite before hydrothermal treatment. The effect of some processing parameters like diatomite percentage and Ag-loaded amount on their photocatalytic performance were also investigated in detail by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET, and UV‐Vis spectroscopy. The results show that BiVO4/ diatomite composite photocatalysts can be successfully prepared at 160 °C for the duration of 3h by the hydrothermal process. The diatomite has two significant impacts on their photocatalytic performance: (1) enhancing the dispersion of BiVO4 crystallites due to its high porosity and specific surface area to favor their photocatalytic performance, and (2) having a light screening effect to incident visible light to decrease their photocatalytic activity. Appropriately incorporating diatomite could improve their photocatalytic performance, but the overuse of diatomite would reduce that. Similarly, depositing Ag could effectively improve their photocatalytic activity because of its good light absorption and photosensitive characteristics, but excessive addition would result in their decrease since the overuse of Ag would also promote the electron-hole recombination.

Frictional Performance of an Ionic Liquid/Graphene Composite Additive in Lubricating Oil

NANO ◽  
2021 ◽  
pp. 2150111
Author(s):  
Shengli You ◽  
Ming Zhou ◽  
Mingyue Wang ◽  
Xin Chen ◽  
Long Jin ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Friction Pair ◽  
Testing Machine ◽  
Steel Ball ◽  
Wear Scar ◽  
Wear Testing ◽  
Lubricating Oil ◽  
Wear Scar Diameter ◽  
Base Oil ◽  
Frictional Performance

In this study, we used a four-ball friction and wear testing machine to test the tribological properties of [HPy]BF4 ionic liquids (ILs), low-layer graphene (G), and IL and G compounds (IL/G) as lubricant additives at variousconcentrations, loads, and speeds. The morphology of the wear scar was characterized by a white-light interferometer and a scanning electron microscope (SEM). The results showed that the optimal concentrations of IL and G were 0.10[Formula: see text]wt.% and 0.05[Formula: see text]wt.%, respectively. When the IL concentration was 0.10[Formula: see text]wt.%, the friction coefficient and the wear scar diameter (WSD) reduced by approximately 18% and 8%, respectively, compared to the base oil. When the concentration of G was 0.05[Formula: see text]wt.%, the friction coefficient and WSD reduced by approximately 23% and 12%, respectively, compared to the base oil. After adding the optimal concentration of the IL/G composite additive under the same test conditions, the average friction coefficient of the steel ball reduced by approximately 30%, and the average WSD reduced by approximately 18%. IL/G nanoadditives could be easily attached to the pit area on the friction surface of the steel ball, which made the contact surface of the friction pair smoother and the area of the oil film bearing the load larger, compared to those using the base oil. These two combined phenomena promoted synergistic antifriction and antiwear effects, which significantly improved the frictional performance of the base oil.

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