Preparation and tribological properties of BN/calcium borate nanocomposites as additive in lubricating oil

2018 ◽  
Vol 70 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Yanfei Yang ◽  
Xiaobo Wang ◽  
Sen Mei ◽  
Xing Zhu ◽  
Shiqiang Chen ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Optical Microscope ◽  
Lubricating Oil ◽  
Core Shell ◽  
Calcium Borate ◽  
Wear Area ◽  
Content Type ◽  
X Ray ◽  
Friction Tester ◽  
Transmission Electron

Purpose The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil. Design/methodology/approach BCBNs were prepared by heterogeneous deposition method. And the morphology and structure of samples were analysed by transmission electron microscopy, Fourier transform infrared spectra and X-ray powder diffraction pattern. The maximum non-seizure load (PB) of samples was tested using four-ball friction tester. The average friction coefficients and wear tracks were obtained. In addition, tribological mechanism was also investigated using optical microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscope. Findings It was found that the nanocomposites present core-shell nanostructure with the thickness of shell around 12 nm and the diameter of particles 100-200 nm, and tribological tests indicate that the PB value of BCBNs was increased by 113 per cent, whereas the average friction coefficient was decreased by 23.6 per cent and the bloom’s wear area was also decreased by 25.2 per cent. Originality/value This paper involves investigation on tribological properties and mechanism of the BCBNs with core-shell structure.

Preparation and tribological properties of complex nanoparticle styrene/calcium borate with core-shell structure

2014 ◽  
Vol 66 (4) ◽  
pp. 525-532 ◽  
Author(s):  
Liu Ping ◽  
Wang Dongyun ◽  
Li Yanbin ◽  
Guo Yanqing ◽  
Hao Lifeng
Keyword(s):  
Tribological Properties ◽  
Shell Structure ◽  
Lubricating Oil ◽  
Structure Characteristic ◽  
Core Shell ◽  
Calcium Borate ◽  
Content Type ◽  
X Ray ◽  
Novel Complex ◽  
Core Shell Structure

Purpose – The purpose of this paper is to develop a potential nanoparticles lubricant additive for solving the problem of the insolubility and stable dispersity; the complex nanoparticles with core-shell structures are less studied in the field. Therefore, this paper determines novel complex nanoparticles and their tribological properties. Design/methodology/approach – According to the conventional preparation method, the complex nanoparticle styrene/calcium borate (PS/O-CaB) was synthesized. The microstructures of the as-obtained samples were characterized by X-ray diffraction infrared spectroscopy and thermogravimetric analysis. Tribological properties of PS/O-CaB used as lubricating oil additive were evaluated on four-ball tribometer. The worn surface of the steel ball was investigated by a three-dimensional non-contact surface profilometer and X-ray photoelectron spectroscopy (XPS). Findings – The results of the structure characteristic indicate two different crystalline forms, namely, Ca2B6O11 and Ca2B2O5, and the average size of calcium borate nanoparticles in PS/O-CaB is about 20-40 nm. Moreover, the good tribological properties are due to a wear resistance film containing both depositions and the tribochemical reaction products which comprise B2O3, FeB and Fe2O3. Originality/value – Novel complex nanoparticles with core-shell structure (PS/O-CaB) were successfully prepared. Moreover, the PS/O-CaB shows excellent tribological capacity such as load-carrying, friction-reducing and antiwear property.

Synthesis and tribological properties of nanogrease

2018 ◽  
Vol 70 (3) ◽  
pp. 512-518 ◽  
Author(s):  
Alaa Mohamed ◽  
Mohamed Hamdy ◽  
Mohamed Bayoumi ◽  
Tarek Osman
Keyword(s):  
Electron Microscopy ◽  
Tribological Properties ◽  
Power Efficiency ◽  
New Technologies ◽  
Mechanical Equipment ◽  
Content Type ◽  
Base Oil ◽  
X Ray ◽  
Transmission Electron ◽  
Steel Balls

Purpose To enhance the tribological properties of nanogrease, one of the new technologies was used to synthesize a nanogrease having carbon nanotubes (CNTs) nanoparticles (NPs) with different concentrations. The microstructures of the synthesized NPs were characterized and evaluated by x-ray diffraction spectroscopy (XRD) and transmission electron microscopy (TEM). Tribological properties of the nanogrease were evaluated using a four-ball tester. The worn surface of four steel balls was investigated by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX). Design/methodology/approach Grease was dissolved in chloroform (10 Wt.%), at 25 °C for 1 h. In parallel, functionalized CNTs with different volume concentrations (0.5, 1, 2 and 3 Wt.%) were dispersed in N, N-dimethylformamide. The mixture was stirred for 15 min and then sonicated (40 kHz, 150 W) for 30 min. After that, the mixture was added to the grease solution and magnetically stirred for 15 min and then sonicated for 2 h. Findings The results suggested that CNTs can enhance the antiwear and friction properties of nanogrease at 0.5 Wt.% CNTs to about 57 and 48 per cent, respectively. In addition, the weld load of the base oil containing 0.5 Wt.% CNTs was improved by 17 per cent compared with base grease. Originality/value This work describes the inexpensive and simple fabrication of nanogrease for improving the properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

New eco-friendly anticorrosive core-shell pigments

2015 ◽  
Vol 44 (5) ◽  
pp. 276-291 ◽  
Author(s):  
Nivin M Ahmed ◽  
Walaa M. Abd El-Gawad ◽  
Elham A. Youssef ◽  
Eglal R. Souaya
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Ceramic Composites ◽  
Core Shell ◽  
Chemical Compositions ◽  
Corrosion Properties ◽  
Content Type ◽  
X Ray ◽  
Transmission Electron ◽  
Steel Substrates

Purpose – The purpose of this paper is to present the preparation of core-shell ferrites/kaolin pigments and comparing their efficiency in protecting metal substrates to original ferrites which were also prepared. Core-shell structured particles are recently gaining lots of importance due to their exciting applications in different fields; these particles are constructed from cores and shells of different chemical compositions which show ultimately distinctive properties of varied materials different from their counterparts. The new core-shell pigment is based on shell of different ferrites that comprises only 10-20 per cent of the whole pigment on kaolin (cores) which is a cheap and abundant ore that comprises 80-90 per cent of the prepared pigment. The new pigments do not only comprise two different components, but they also contain pigment and extender in the same compound; their loadings in the paint formulations ranges from 50 and 75 per cent of the whole pigment. The work showed that these eco-friendly and cheap core-shell pigments are comparable in their efficiency to that of ferrites in protecting steel substrates. Design/methodology/approach – The different ferrites and ferrites/kaolin pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray fluorescence, X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDAX) and transmission electron microscopy (TEM). Evaluation of these pigments was done using international standard testing methods (ASTM). After evaluation, the pigments were incorporated in solvent-based paint formulations based on medium oil-modified soya-bean dehydrated castor oil alkyd resin. The physico-mechanical properties of dry films and their corrosion properties using accelerated laboratory test in 3.5 per cent NaCl for 28 days were determined. Findings – The results of this work revealed that ferrite/kaolin core-shell pigments were close in their performance to that of the ferrite pigments in protection of steel, and at the same time, they verified good physico-mechanical properties. Practical implications – Treated kaolin can be applied in many industries beside pigment manufacture and paint formulations; it can be applied as reinforcing filler in rubber, plastics and ceramic composites. Also, it is applied in paper filling, paper coatings and electrical insulation. Originality/value – Ferrite and ferrite/kaolin are environmentally friendly and can replace other hazardous pigments (e.g. chromates) with almost the same quality in their performance; also, they can be used in industries other than paints, for example paper, rubber and plastics composites.

Preparation and evaluation of tribological properties of oil-soluble rice-like CuO nanoparticles

2015 ◽  
Vol 67 (3) ◽  
pp. 276-283 ◽  
Author(s):  
Hao Liu ◽  
Yujuan Zhang ◽  
Shengmao Zhang ◽  
Yanfen Chen ◽  
Pingyu Zhang ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Normal Load ◽  
Cuo Nanoparticles ◽  
Lubricating Oil ◽  
Infrared Spectrometry ◽  
Environment Friendly ◽  
Content Type ◽  
X Ray ◽  
Oil Additives ◽  
Lubricating Oil Additives

Purpose – The purpose of this paper is synthesis of oil-soluble non-spherical nanoparticles modified with free phosphorus and sulphur modifier and investigation of their tribological properties as environment-friendly lubricating oil additives. Design/methodology/approach – To study the effect of morphology of nanoparticles on their tribological properties, rice-like CuO nanoparticles were synthesized. To improve the solubility of CuO nanoparticles in organic media, the in-situ surface modification method was used to synthesize these products. The morphology, composition and structure of as-synthesized CuO nanoparticles were investigated by means of transmission electron microscopy, X-ray powder diffraction, thermogravimetric analysis and Fourier transform infrared spectrometry. The tribological properties of as-synthesized CuO nanoparticles as an additive in liquid paraffin (LP) were evaluated with a four-ball tribometer. The morphology and elemental composition of worn steel ball surfaces were analysed by X-ray photoelectron spectroscopy. Findings – It has been found that as-synthesized CuO nanoparticles with rice-like morphology have an average size of 7 and 15 nm along the shorter axle and longer axle, respectively, and can be well-dispersed in LP. Tribological properties evaluation results show that as-synthesized CuO nanoparticles as additives in LP show good friction-reducing, anti-wear and load-carrying capacities, especially under a higher normal load. Originality/value – Oil-soluble rice-like CuO nanoparticles without phosphorus and sulphur were synthesized and their tribological properties as lubricating oil additives were also investigated in this paper. These results could be very helpful for application of CuO nanoparticles as environment-friendly lubricating oil additives, owing to their free phosphorus and sulphur elements characteristics.

Study on the corrosion protection performance of new ferrite/kaolin core-shell pigments in epoxy-based paints

2015 ◽  
Vol 63 (1) ◽  
pp. 36-46 ◽  
Author(s):  
Nivin M Ahmed ◽  
Walaa M. Abd El-Gawad ◽  
Eglal R. Souaya
Keyword(s):  
Mechanical Properties ◽  
Corrosion Protection ◽  
Cost Savings ◽  
Core Shell ◽  
Corrosion Properties ◽  
Content Type ◽  
X Ray ◽  
Transmission Electron ◽  
Paint Films ◽  
Steel Substrates

Purpose – The purpose of this study is to prepare core-shell ferrites/kaolin pigments and compare their efficiency in protecting metal substrates to original ferrites. The new pigments are based on precipitating a shell of different ferrites that comprise only 10-20 per cent of the whole pigment on kaolin (core), which is a cheap and abundant ore comprising 80-90 per cent of the prepared pigment. These new pigments combine the properties of both its core and shell counter-parts, exhibiting improved corrosion protection properties. Furthermore, the pigments are represented as efficient, economically feasible and eco-friendly with comparable efficiency to that of original ferrites in protecting steel substrates. Design/methodology/approach – The new pigments were characterized using different analytical and spectrophotometric techniques, e.g. transmission electron microscopy, energy-dispersive X-ray analysis and X-ray fluorescence. The pigments were then incorporated in epoxy-based paint formulations. The physico-mechanical properties of dry films and their corrosion properties were tested using accelerated laboratory tests in 3.5 per cent NaCl for 28 days. Findings – The results of this study revealed that ferrite/kaolin core-shell pigments performance was almost close to that of the ferrite pigments in the protection of steel, and, at the same time, they confirmed good physico-mechanical properties. Practical implications – These pigments can be applied in other polymer composites, e.g. rubber and plastics, as fillers and reinforcing agents. Originality/value – Ferrite and ferrite/kaolin are environmentally friendly pigments, and they can impart high anticorrosive behavior to paint films with concomitant cost savings.

Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

Synthesis of Trilaminar Core–Shell Au/α-Fe2O3@SnO2Nanocomposites and their Application for Nonenzymatic Dopamine Electrochemical Sensing

NANO ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. 1950138 ◽  
Author(s):  
Sai Zhang ◽  
Shijun Yue ◽  
Jiajia Li ◽  
Jianbin Zheng ◽  
Guojie Gao
Keyword(s):  
Electron Microscopy ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Synthesis Process ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Stability ◽  
Transmission Electron

Au nanoparticles anchored on core–shell [Formula: see text]-Fe2O3@SnO2 nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/[Formula: see text]-Fe2O3@SnO2 trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5[Formula: see text][Formula: see text]M to 0.47[Formula: see text]mM, a low detection limit of 0.17[Formula: see text][Formula: see text]M (S/[Formula: see text]) and high sensitivity of 397.1[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text]. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

Experimental analysis of tribological properties of ultrasonically dispersed garnet nanoparticles in SN500 grade lubricating oil

2018 ◽  
Vol 70 (2) ◽  
pp. 250-255 ◽  
Author(s):  
Maheswaran R. ◽  
Sunil J.
Keyword(s):  
Tribological Properties ◽  
Lubricating Oil ◽  
Additive Concentration ◽  
Two Phase ◽  
Content Type ◽  
Lubricant Oil ◽  
Surface Polishing ◽  
Frequent Monitoring ◽  
Chemical Content ◽  
Solid Liquid

Purpose The optimal performance of the machinery is based on lubricants that require frequent monitoring and the analysis of characteristics such as chemical content, contamination and viscosity. The application of nanoparticles dispersed lubricant in tribology has received remarkable attention in recent years. This paper aims to investigate the tribological properties of SN500 grade lubricating oil containing garnet nanoparticles. Design/methodology/approach In this study, 45-nm-sized garnet particles are ultrasonically dispersed in SN500 grade base lubricant oil. The effects of viscosity and additive concentration on tribological properties are investigated using a four-ball tester. Findings Rolling, reinforcing and film-forming behaviour of dispersed nano-sized garnet additives in the rubbing zone were investigated using scanning electron microscopy equipped with energy dispersive spectroscopy. The results indicate that the garnet additives can improve the wear resistance and resistance to relative motion and decrease the friction coefficient of rubbing steel interface by surface polishing and formation of tribo-film containing Si, C and Mn. Originality/value Because of the complex two-phase solid–liquid mixture, there are still limited physical understandings of the friction and wear reduction mechanisms. Therefore, the present research was undertaken to interpret the possible phenomena.

Growth and Optical Properties of GaP, GaP@GaN and GaN@GaP Core-shell Nanowires

2003 ◽  
Vol 776 ◽  
Author(s):  
Hung-Min Lin ◽  
Jian Yang ◽  
Yong-Lin Chen ◽  
Yau-Chung Liu ◽  
Kai-Min Yin ◽  
...  
Keyword(s):  
Phonon Mode ◽  
Piezoelectric Effect ◽  
Lattice Mismatch ◽  
Core Shell ◽  
Photoluminescence Intensity ◽  
X Ray ◽  
Transmission Electron ◽  
Vapor Deposition Technique ◽  
Surface Phonon Mode ◽  
Shell Nanowires

AbstractHigh-quality GaP, GaP@GaN and GaN@GaP nanowires were grown by a convenient vapor deposition technique. The wire-like and two-layers structures of GaP@GaN and GaN@GaP core-shell nanowires were clearly resolved using X-ray powder diffraction and high-resolution transmission electron microscopy (HRTEM) and their growth directions were identified. Photoluminescence intensity of GaP@GaN nanowires increased as temperature increased. The result was interpreted by the piezoelectric effect induced from lattice mismatch between two semiconductor layers. An unexpected peak at 386 cm-1 was found in the Raman spectra of GaN@GaP and assigned to a surface phonon mode due to the interface. Detailed synthetic conditions and possible growth mechanisms of those nanowires were proposed.

scholarly journals Fe based core–shell model catalysts for the reaction of CO2 with H2

2020 ◽  
Vol 131 (1) ◽  
pp. 119-128 ◽  
Author(s):  
Johann Kirchner ◽  
Christian Zambrzycki ◽  
Zeynep Baysal ◽  
Robert Güttel ◽  
Sven Kureti
Keyword(s):  
Shell Model ◽  
Photoelectron Spectroscopy ◽  
Major Product ◽  
Model Catalysts ◽  
Core Shell ◽  
Core Size ◽  
X Ray ◽  
Transmission Electron ◽  
Spent Catalysts ◽  
Temperature Programmed

Abstract Fe@SiO2 core–shell model catalysts were investigated for the conversion of CO2 and H2 into CH4, CO and H2O. For evaluation of the effect of core size on the catalytic activity, samples with Fe particle sizes of 4, 6 and 8 nm were prepared. Fresh and spent catalysts were thoroughly characterized by X-ray diffraction, 57Fe Mössbauer spectroscopy, transmission electron microscopy, temperature programmed hydrogenation and X-ray photoelectron spectroscopy. As a result, the yield of the major product CO as well as CH4 was increased with Fe core size. Additionally, growing Fe cores led to stronger carburization and higher amount of reactive carbide entities, which drive the CH4 formation. Finally, formation of inactive bulk carbon deposition is strongly suppressed for the core–shell catalysts in comparison to bulk iron oxide catalysts used for CO2 hydrogenation.

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