Synthesis and tribological study of core-shell Ag@polyaniline as lubricant additive in lithium-based complex grease

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yanqiu Xia ◽  
Chen Chen ◽  
Xin Feng ◽  
Zhengfeng Cao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fourier Transforms ◽  
Friction Pair ◽  
Lubricant Additive ◽  
Friction Reduction ◽  
Core Shell ◽  
Protective Film ◽  
Simple Method ◽  
Content Type ◽  
Lubrication Mechanisms

Purpose The purpose of this paper is to synthesize a kind of core-shell Ag@polyaniline (Ag@PAN) as a lubricant additive to improve the friction reduction and anti-wear abilities of lithium-based complex grease. Design/methodology/approach The core-shell Ag@PAN was prepared by a simple method and was introduced into the lithium-based complex grease. The typical properties of Ag@PAN were investigated by scanning electron microscopy (SEM), Fourier transforms infrared spectrometer and thermal gravimetric analyzer. The tribological properties were evaluated under different conditions. After the tribological test, the worn surface was analyzed by SEM and X-ray photoelectron spectroscopy to probe the lubrication mechanisms. Findings The prepared Ag@PAN could greatly improve the friction reduction and wear resistance of the friction pair under different conditions. The preferable tribological performances were mainly attributed to the synergism of various lubrication mechanisms including “mending effect,” “rolling effect” and lubricating protective film, and so on. Originality/value This study synthesizes a new kind of core-shell Ag@PAN as a lubricant additive, and it possesses preferable friction reduction and anti-wear abilities.

Polyaniline as an additive towards improving tribological properties and anti-corrosion performance of ionic liquids-based greases

2020 ◽  
Vol 72 (7) ◽  
pp. 851-856
Author(s):  
Zhengfeng Cao ◽  
Yanqiu Xia ◽  
Chuan Chen ◽  
Kai Zheng ◽  
Yi Zhang
Keyword(s):  
Ionic Liquids ◽  
Peer Review ◽  
Tribological Properties ◽  
Photoelectron Spectroscopy ◽  
Salt Spray ◽  
Lubricant Additive ◽  
Friction Reduction ◽  
Content Type ◽  
Base Oil ◽  
Worn Surfaces

Purpose This paper aims to explore polyaniline (PANI) as a lubricant additive to improve the anti-corrosion and tribological properties of ionic liquids (ILs) for actual applications. Design/methodology/approach ILs were synthesized by dissolving lithium salts in synthetic oil and were used as a base oil to prepare ILs-based greases. PANI was used as an additive. The tribological properties were investigated in detail and the anti-corrosion ability was also assessed via salt spray test. After friction test, the worn surfaces were characterized by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy to analyze the lubrication mechanisms. Findings PANI not only reduces the corrosion but also improves the friction reduction and anti-wear abilities of the ILs-based greases. The analysis indicates that the protective films generated on the worn surfaces were responsible for the preferable anti-corrosion and tribological properties. Originality/value This paper provides an effective approach to improve the anti-corrosion and tribological properties of ILs for actual applications. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2019-0469/

A simple method to prepare carbon nanotubes from sunflower seed hulls and sago and their application in supercapacitor

2015 ◽  
Vol 44 (1) ◽  
pp. 7-12 ◽  
Author(s):  
H.Y. Zhang ◽  
H.J. Niu ◽  
Y.M. Wang ◽  
C. Wang ◽  
X.D. Bai, ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Sunflower Seed ◽  
Electrochemical Impedance ◽  
Cyclic Voltammograms ◽  
Production Scale ◽  
Simple Method ◽  
Content Type ◽  
X Ray

Purpose – The purpose of this paper was to provide a simple method for the preparation of carbon nanotubes (CNTs) by pyrolysing sunflower seed hulls and sago and to evaluate the application of such CNTs in supercapacitors. Design/methodology/approach – The CNTs were obtained by pyrolysing sunflower seed hulls and sago at 800°C. The prepared CNTs were studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, cyclic voltammograms, galvanostatic charge and discharge and electrochemical impedance spectra methods. Findings – The CNTs had large surface areas as determined by the methylene blue method and the Brunauer – Emmett – Teller method. And the CNTs that were prepared by pyrolysing the natural sunflower seed hulls (denoted as CNTs-1) and sago (denoted as CNTs-2) had capacitances of 86.9 F/g and 26.7 F/g, respectively. Research limitations/implications – The capacitances of CNTs can be further improved. Practical implications – The exceptional electronic and mechanical properties of CNTs prepared lend the CNTs to diverse applications including electrocatalysts, hydrogen storage, photovoltaic devices actuators, energy storage, field-emitting flat panel displays and composites. Originality/value – Currently, CNTs have not yet been used in the industry at a mass production scale due to high costs associated. The outcomes of the study reported in this article could provide a convenient method in aid of industrialisation of the production of CNTs.

The tribochemical study of novel phosphorous-nitrogen (P-N) type phosphoramidate additives in water

2014 ◽  
Vol 66 (3) ◽  
pp. 346-352 ◽  
Author(s):  
Jincan Yan ◽  
Xuefeng Bai ◽  
Jing Li ◽  
Tianhui Ren ◽  
Yidong Zhao
Keyword(s):  
Tribological Properties ◽  
Lubricant Additive ◽  
Protective Film ◽  
The Novel ◽  
Edge Structure ◽  
Content Type ◽  
Wear And Friction ◽  
X Ray Absorption ◽  
Commercial Lubricant ◽  
Reducing Properties

Purpose – The purpose of this paper is to investigate the tribological properties of novel phosphorous-nitrogen (P-N) type additives in water. Design/methodology/approach – The tribological properties of the novel P-N additives in water are compared with a commercial lubricant additive of the P-N type using a four-ball machine. The tribological mechanism was investigated by X-ray absorption near-edge structure (XANES) spectroscopy. Findings – The experimental results indicate that the phosphoramidate derivatives possess good anti-wear and friction-reducing properties. The XANES analysis shows that the prepared compounds can form a protective film containing phosphate and/or polyphosphate that affects the tribological behavior. Originality/value – The purpose of this paper is to investigate the tribological properties of the novel P-N type additives in water.

Stabilization of silica-coated silver iodide nanoparticles by ethanol-washing

2016 ◽  
Vol 45 (2) ◽  
pp. 99-105
Author(s):  
Yoshio Kobayashi ◽  
Tetsuya Ayame ◽  
Kyosuke Shibuya ◽  
Tomohiko Nakagawa ◽  
Yohsuke Kubota ◽  
...  
Keyword(s):  
Shell Structure ◽  
Silver Iodide ◽  
Colloid Solution ◽  
Core Shell ◽  
Simple Method ◽  
Content Type ◽  
X Ray ◽  
The Core ◽  
Core Shell Structure ◽  
Ethanol Washing

Purpose – This paper aims to propose a simple method for stabilizing silica-coated silver iodide (AgI/SiO2) core-shell particles, of which a colloid solution functions as an X-ray contrast agent. Design/methodology/approach – A colloid solution of AgI nanoparticles was prepared by mixing silver perchlorate and potassium iodide in water. The AgI/SiO2 nanoparticles were fabricated by a sol-gel method using NaOH, H2O and tetraethylorthosilicate in ethanol in the presence of AgI nanoparticles surface-modified with 3-mercaptopropyltrimethoxysilane. Findings – The silica shells of AgI/SiO2 particles were dissolved near the AgI nanoparticle surface, when they were washed by a process composed of centrifugation, removal of supernatant with decantation, addition of water as a washing solution and a shake with a vortex mixer. In contrast, the shells were not damaged by using ethanol as the washing solution, i.e. ethanol-washing. An X-ray photoelectron spectroscopy spectrum of the silica was changed after the ethanol-washing, which indicated that the ethanol-washing had an effect on the chemical bonds in silica. The effect also acted on the silica shells of AgI/SiO2 particles, which did not damage the core-shell structure, i.e. controlled the dissolution of shell. Originality/value – The paper demonstrates that the ethanol-washing is quite useful for stabilizing the core-shell structure composed of the silica shells.

scholarly journals Co@ag Core–Shell Nanomaterials: Preparation and Application in the Purification of Yellow River Water

2021 ◽  
Author(s):  
Guochao Zhang ◽  
Yingying Zhao ◽  
Yanjun Lai ◽  
Shuai He ◽  
Qi Gao ◽  
...  
Keyword(s):  
River Water ◽  
Photoelectron Spectroscopy ◽  
Quantitative Methods ◽  
Yellow River ◽  
Core Shell ◽  
Negative Bacterium ◽  
Bacteriostatic Effect ◽  
Simple Method ◽  
Gram Negative ◽  
X Ray

Abstract In this study, we prepared a new type of recyclable Co@Ag core–shell nanomaterials with a very simple method named displacement reaction. Co@Ag core–shell nanomaterials were prepared in AgNO3 solution with cobalt nanomaterials as the core, while the surface was coated with silver nanomaterials. Co@Ag core–shell nanomaterials were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and oscillating sample magnetometer (VSM).We found that the diameter of the Co@Ag core–shell nanomaterials was about 100nm, which was exhibited in form of elemental elements andobvious magnetic properties.In order to evaluate the bacteriostatic effect of Co@Ag core–shell nanomaterials, we used qualitative and quantitative methods to assess the bacteriostatic effect of these materials on standard strains of Pseudomonas aeruginosa (ATCC27853, Gram - negative bacterium), Staphylococcus aureus (ATCC 25923, Gram-positive bacterium), Escherichia coli (ATCC 25922, Gram-negative bacterium) and Candida albicans (ATTC 90029, yeast) in Yellow River water in vitro. The results show that Co@Ag core–shell nanomaterials have a significant antibacterial effect. In addition, Co@Ag core–shell nanomaterials can be recycled through an external magnetic field to reduce environmental pollution. Interestingly, the reclaimed Co@Ag core–shell nanomaterials can still have antibacterial activity and can be reused. These results indicate that Co@Ag core–shell nanomaterials may have potential application as disinfectants for water.

Tribological properties of carbonized polydopamine/rGO composite coatings

2019 ◽  
Vol 72 (1) ◽  
pp. 54-65
Author(s):  
Ming Yang ◽  
Zhengfeng Jia ◽  
Denghu Wei ◽  
Yunxia Wang ◽  
Xianjuan Pang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Tribological Properties ◽  
Photoelectron Spectroscopy ◽  
Composite Coatings ◽  
Copper Substrate ◽  
Friction Reduction ◽  
Wear Properties ◽  
Content Type ◽  
X Ray

Purpose The purpose of this paper is to investigate the tribological properties of carbonized polydopamine/reduced graphene oxide (CPDA/rGO) composite coatings. Design/methodology/approach CPDA/rGO composite coatings were prepared using the spray technique and subsequent pyrolysis under argon. The transmission electron microscopy, field-emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy revealed the conversion of PDA and GO into CPDA and rGO, respectively. Findings The results of tribological investigations show that the CPDA/rGO composite coatings with heat treatment at 300°C possess much better friction-reduction and anti-wear properties. Originality/value The worn surfaces of the PDA/GO composite films after heat treatment at 300°C were much smoother than that of the copper substrate. The tribofilms containing C, N, O and Cu played an important role on reducing friction and increasing wear resistance.

scholarly journals Chemical in‐depth analysis of (Ca/Sr)F 2 core–shell like nanoparticles by X‐ray photoelectron spectroscopy with tunable excitation energy

2021 ◽  
Vol 53 (5) ◽  
pp. 494-508
Author(s):  
Anja Müller ◽  
Thoralf Krahl ◽  
Jörg Radnik ◽  
Andreas Wagner ◽  
Carsten Kreyenschulte ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Photoelectron Spectroscopy ◽  
Core Shell ◽  
X Ray ◽  
Depth Analysis

Performance of coatings containing treated silica fume in the corrosion protection of reinforced concrete

2018 ◽  
Vol 47 (4) ◽  
pp. 350-359 ◽  
Author(s):  
Nivin M. Ahmed ◽  
Mostafa G. Mohamed ◽  
Reham H. Tammam ◽  
Mohamed R. Mabrouk
Keyword(s):  
Reinforced Concrete ◽  
Silica Fume ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Dual Function ◽  
Core Shell ◽  
Protection Efficiency ◽  
Content Type ◽  
Anticorrosive Pigments

Purpose This study aims to apply novel anticorrosive pigments containing silica fume-phosphates (Si-Ph), which were prepared using core-shell technique by covering 80-90 per cent silica fume (core) with 10-20 per cent phosphates (shell) previously, to play dual functions simultaneously as anticorrosive pigments in coating formulations and as an anticorrosive admixture in concrete even if it is not present in the concrete itself. Two comparisons were held out to show the results of coatings on rebars containing core-shell pigments in concrete, and concrete admixtured with silica fume can perform a dual function as anticorrosive pigment and concrete admixture. The evaluation of corrosion protection efficiency of coatings containing core-shell pigments and those containing phosphates was performed. Design/methodology/approach Simple chemical techniques were used to prepare core-shell pigments, and their characterization was carried out in a previous work. These pigments were incorporated in solvent-based paint formulations based on epoxy resin. Different electrochemical techniques such as open-circuit potential and electrochemical impedance spectroscopy were used to evaluate the anticorrosive efficiency of the new pigments. Findings The electrochemical measurements showed that concrete containing coated rebars with core-shell pigments exhibited almost similar results to that of concrete admixtured with silica fume. Also, the anticorrosive performance of coatings containing Si-Ph pigments offered protection efficiency almost similar to that of phosphates, proving that these new pigments can perform both roles as anticorrosive pigment and concrete admixture. Originality/value Although the new Si-Ph pigments contain more than 80 per cent waste material, its performance can be compared to original phosphate pigments in the reinforced concrete.

scholarly journals Tribological Behaviour of Graphene Nanoplatelets as Additive in Pongamia Oil

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 732
Author(s):  
Yeoh Jun Jie Jason ◽  
Heoy Geok How ◽  
Yew Heng Teoh ◽  
Farooq Sher ◽  
Hun Guan Chuah ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Graphene Nanoplatelets ◽  
Friction Reduction ◽  
Engine Oil ◽  
Protective Film ◽  
Tribological Behaviour ◽  
Wear Reduction ◽  
Pongamia Oil ◽  
Interacting Surfaces ◽  
Worn Surface

This study investigated the tribological behaviour of Pongamia oil (PO) and 15W–40 mineral engine oil (MO) with and without the addition of graphene nanoplatelets (GNPs). The friction and wear characteristics were evaluated in four-ball anti-wear tests according to the ASTM D4172 standard. The morphology of worn surfaces and the lubrication mechanism of GNPs were investigated via SEM and EDS. This study also focuses on the tribological effect of GNP concentration at various concentrations. The addition of 0.05 wt % GNPs in PO and MO exhibits the lowest friction and wear with 17.5% and 12.24% friction reduction, respectively, and 11.96% and 5.14% wear reduction, respectively. Through SEM and EDS surface analysis, the surface enhancement on the worn surface by the polishing effect of GNPs was confirmed. The deposition of GNPs on the friction surface and the formation of a protective film prevent the interacting surfaces from rubbing, resulting in friction and wear reduction.

Tribological effects of laser surface texturing and residual stress

2018 ◽  
Vol 70 (1) ◽  
pp. 126-132 ◽  
Author(s):  
Shuwen Wang ◽  
Feiyan Yan ◽  
Ao Chen
Keyword(s):  
Residual Stress ◽  
Wear Resistance ◽  
Friction And Wear ◽  
Surface Texturing ◽  
Laser Surface ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Wear Testing ◽  
Content Type ◽  
Surface Textures

Purpose The purpose of this paper is to investigate the tribological effects of laser surface texturing (LST) and residual stress on functional surfaces. Design/methodology/approach Three different surface textures (circular dimple, elliptical dimple and groove) with two different textured area ratios (10 and 20 per cent) are designed and fabricated by a Picosecond Nd YAG Laser machine. The friction and wear performance of textured specimens is tested using a UMT-2 friction and wear testing machine in mixed lubrication. Findings Test results show that elliptical dimples exhibit the best performance in wear resistance, circular dimples in friction reduction and grooves in stabilization of friction. The surfaces with larger textured area density exhibit better performance in both friction reduction and wear resistance. The improved performance of LST is the coupled effect of surface texture and residual stress. Originality/value The findings of this study may provide guidance for optimal design of functional surface textures in reciprocating sliding contacts under mixed or hydrodynamic lubrication, which can be used in automotive and other industrial applications.

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