Preparation and tribological properties of a microemulsion for magnesium alloy warm rolling

2019 ◽  
Vol 71 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Chang Dong ◽  
Jianlin Sun ◽  
Zixuan Cheng ◽  
Yuqing Hou
Keyword(s):  
Magnesium Alloy ◽  
Surface Morphology ◽  
Tribological Properties ◽  
Warm Rolling ◽  
Friction Reduction ◽  
Alloy Strip ◽  
Lubrication Mechanism ◽  
Content Type ◽  
Rolling Oil ◽  
Lubrication Properties

Purpose The purpose of this paper is to synthesize a microemulsion and investigate its tribological properties as lubricant. Magnesium alloy warm rolling experiments were conducted. Surface morphology was observed and wear form was summarized. The composition of surface residues was analyzed, which sheds light on the lubrication mechanism of microemulsion. Design/methodology/approach A microemulsion was prepared with a proper amount of oil, surfactant, cosurfactant, water and other additives for magnesium alloy strip warm rolling. Tribological properties, such as maximum non-seizure load (PB), friction coefficient (μ) and wear scar diameter (D) of the microemulsion were measured and compared with those of emulsion and rolling oil on an MR-10A four-ball tribotester. The extreme pressure anti-wear coefficients (O) were calculated and compared. Warm rolling experiments were carried out on a Ф 170/400 × 300 mm four-high rolling mill at 240°C to compare the finish rolling thickness and surface quality of rolled AZ31B magnesium alloy strip under four lubrication states, namely, no lubrication, rolling oil, microemulsion and emulsion. The surface morphology after warm rolling was observed with confocal laser scanning microscope and scanning electron microscope, respectively. The composition of surface residues was analyzed with energy dispersive spectrometry and X-Ray photoelectron spectroscopy. Findings Surface morphology indicated that pitting wear, adhesive wear and ploughing wear were three main forms of wear in magnesium alloy warm rolling. Microemulsion had excellent lubrication properties with less residual oil remaining. Two types of adsorption layers formed on magnesium alloy strip surface were responsible for lubrication properties. MgSO4 and magnesium stearate in the reaction layer played a key role in anti-wear and friction-reduction in warm rolling. Originality/value The study is original and gives valuable information on lubrication mechanism of microemulsion in warm rolling of magnesium alloy strips.

Effect of MWCNTs/Talc powder nanoparticles on the tribological and thermal conductivity performance of calcium grease

2019 ◽  
Vol 72 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Ahmed Mobasher ◽  
Alaa Khalil ◽  
Medhat Khashaba ◽  
Tarek Osman
Keyword(s):  
Thermal Conductivity ◽  
Tribological Properties ◽  
Power Efficiency ◽  
Friction Reduction ◽  
Wear Testing ◽  
Mechanical Equipment ◽  
Content Type ◽  
Transmission Electron ◽  
Nano Additives ◽  
Pin On Disk

Purpose The purpose of this paper is to evaluate the influence of nanoparticles as an additive on the tribological properties of calcium grease. Design/methodology/approach The nano additives in this research are with different concentration of multi carbon nanotubes (MWCNTs) and Talc powder (1, 2, 3, 3 and 5 per cent). The ratio of MWCNTs to Talc powder is 1:1. The tribological properties of hyper MWCNTs/Talc powder to calcium grease were evaluated using a pin-on-disk wear testing. The results show that the nano additives MWCNTs/Talc to calcium grease exhibit good performance in anti-wear and friction reduction. The action mechanism was estimated through analysis of the worm surface with x-ray diffraction and transmission electron microscope. Findings The result indicates that boundary film mainly composed of MWCNT and Talc powder, and other organic compound was formed on the worm surface during the friction test. In addition, the wear rate and coefficient of friction of nanogreases have shown excellent improvement about 80.62 and 63.44 per cent, respectively, at 4 Wt.% of MWCNTs/Talc powder. Moreover, the thermal conductivity of nanogrease increased about 51.72 per cent. Originality/value This study describes the inexpensive and simple fabrication of nanogrease for improving properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

Preparation and tribological characteristics of graphene/triangular copper nanoplate composites as grease additive

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jing Wang ◽  
Hongying Mi ◽  
Weigui Zhou ◽  
Xin Yang ◽  
Yan He
Keyword(s):  
Tribological Properties ◽  
Self Assembly ◽  
Electrostatic Force ◽  
Friction Reduction ◽  
Tribological Characteristics ◽  
Wear Loss ◽  
Content Type ◽  
X Ray ◽  
Assembly Method ◽  
Theoretical Support

Purpose This study aims to the preparation and tribological characteristics of graphene/triangular copper nanoplate composites (abbreviated as GN/Cu nanoplates) as grease additive and clarifies the growth mechanism and tribological mechanism of GN/Cu nanoplates by different analysis methods. In this paper, it is expected to alleviate the problems of easy aggregation and poor dispersion stability of graphene in lubricants and provide theoretical support for the application of graphene and its composites in the tribology field. Design/methodology/approach In this study, the GN/Cu nanoplates have been successfully prepared by the electrostatic self-assembly method. The structural characteristics of GN/Cu nanoplates were analyzed via transmission electron microscopy and X-ray diffraction. Then the tribological properties of GN/Cu nanoplates were investigated under different loads with SRV-IV [Schwingung, Reibung, Verschleiß (German); oscillating, friction, wear (English translation)] tribotester. White-light interferometry was applied to quantify the wear loss of the disk. The element chemical state on worn surfaces was analyzed by an X-ray photoelectron spectroscope to clarify the tribological mechanism of graphene composites. Findings The electrostatic force between the negative charge of graphene and the positive charge of triangular copper nanoplates promotes the self-assembly of GN/Cu nanoplates. With the addition of GN/Cu nanoplates, the wear loss and average friction coefficient under the load of 200 N have been decreased by 72.6% and 18.3%, respectively. It is concluded that the combined action of graphene deposition film and the copper melting film formed on the worn surface could effectively improve the antiwear ability and friction reduction performance of the grease. Originality/value This manuscript fulfills a new approach for the preparation of GN/Cu nanoplates. At the same time, its tribological properties and mechanism as a lubricating additive were studied which provide theoretical support for the application of graphene and its composites in the tribology field.

Lubrication properties of modified lard and rapeseed oil greases with sodium and lithium thickeners

2015 ◽  
Vol 67 (6) ◽  
pp. 557-563 ◽  
Author(s):  
Juozas Padgurskas ◽  
Raimundas Rukuiža ◽  
Arturas Kupcinskas ◽  
Raimondas Kreivaitis
Keyword(s):  
Wear Resistance ◽  
Tribological Properties ◽  
Rapeseed Oil ◽  
Content Type ◽  
Lithium Soap ◽  
High Thermal Resistance ◽  
Degradable Materials ◽  
Wear Tests ◽  
Lubrication Properties ◽  
Selection Of

Purpose – The purpose of this paper is to conduct research on the possibility of improving the tribological and utilization properties of lard and rapeseed oil bio-based greases by mixing it with ethanol and selection of thickener and modification with special biological additives. Design/methodology/approach – Rapeseed oil- and lard-based greases with sodium and lithium soap thickeners were mixed with either water or ethanol and modified with a special biological anti-wear additive. Tribological properties of modified lubricants evaluated on a four-ball machine. Findings – Rapeseed oil- and lard-based greases suspended in ethanol and modified with bio-additive have the same wear resistance as the industrial non-biological lubrication grease and much higher wear resistance as bio-based reference grease. The tribological efficiency of the additives is higher in greases of rapeseed oil and less efficient in lard-based greases. Oxidation and wear tests show that investigated bio-based greases have comparatively stable tribological properties also after their aging. Modified greases have sufficient consistence according penetration measurements and high thermal resistance according drop-point temperature measurements. All produced experimental greases pass within the category of the easily degradable materials. Originality/value – The greases mixed with the ethanol make possible to form more homogeneous and stable grease mixture. Modified bio-based greases have significantly higher wear resistance as bio-based reference grease, their lubrication properties are stable also after the aging and are categorized as easily degradable materials.

Influence of Thermo-Electropulsing Rolling Process on Microstructure and Mechanical Properties of AZ31 Magnesium Alloy Strip

2013 ◽  
Vol 744 ◽  
pp. 375-378
Author(s):  
Shi Ding Sun ◽  
Guo Yi Tang
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Rolling Process ◽  
Warm Rolling ◽  
Az31 Magnesium Alloy ◽  
Alloy Strip ◽  
Microstructure And Mechanical Properties ◽  
Az31 Mg Alloy ◽  
Short Time ◽  
Electropulsing Treatment

Thermo-electropulsing rolling (TER) process, which combined the electropulsing treatment with the conventional warm rolling process (WR), was applied to manufacture AZ31 magnesium alloy strips in the current study. Influences of TER process and WR process on microstructure and mechanical properties of AZ31 Mg alloy were studied. TER process was found to induce and accelerate the dynamic recrystallization (DRX) behavior of the samples at a relatively low temperature within a short time. Besides, TER process could obtain samples with better mechanical properties than that of WR process.

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/

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.

Deposition and Tribological Properties of CVD Diamond/Diamond-Like Carbon Composite Films

2012 ◽  
Vol 565 ◽  
pp. 615-620
Author(s):  
Bin Shen ◽  
Liang Wang ◽  
Su Lin Chen ◽  
Fang Hong Sun
Keyword(s):  
Surface Morphology ◽  
Composite Film ◽  
Tribological Properties ◽  
Composite Films ◽  
Cvd Diamond ◽  
Carbon Composite ◽  
Dry Sliding ◽  
Diamond Like Carbon ◽  
Dlc Film ◽  
Bonding State

The CVD diamond/diamond-like carbon composite film is fabricated on the WC-Co substrate by depositing a layer of Diamond-like Carbon film on the surface of conventional Micro- or Nano-crystalline diamond film. The hot filament chemical vapor deposition (HFCVD) method and vacuum arc discharge with a graphite cathode are adopted respectively to deposit the MCD/NCD and DLC films. A variety of characterization techniques, including filed emission scanning electron microscope (FE-SEM) and Raman spectroscopy are employed to investigate the surface morphology and atomic bonding state of as-deposited MCD/DLC and NCD/DLC composite film. The results show that both MCD/DLC and NCD/DLC composite films present similar surface morphology with the MCD and NCD films, except for scattering a considerable amount of small-sized diamond crystallites among the grain boundary area. The atomic-bonding state of as-deposited MCD/DLC and NCD/DLC composite films is determined by the top-layered DLC film, which is mainly consisted of amorphous carbon phase and no discernible sp3 characteristic peak can be observed from their Raman spectrum. Furthermore, the tribological properties of as-deposited MCD/DLC and NCD/DLC composite films is examined using a ball-on-plate reciprocating friction tester under both dry sliding and water-lubricating conditions, comparing with conventional DLC, MCD and NCD films. Silicon nitride balls are used as counterpart materials. For the CVD diamond/DLC composite films, the self-lubricating effect of top-layered DLC film is beneficial for suppressing the initial friction peak, as well as shortening the run-in period. The average friction coefficients of MCD/DLC and NCD/DLC composite films during stable sliding period are 0.07 and 0.10 respectively in dry sliding; while under water-lubricating condition, they further decreases to 0.03 and 0.07.

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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