Chemical Understanding of Friction Polymer Based Tribo-Chemical Films Derived From Nanolubricant

2012 ◽  
Author(s):  
Wenyang Zhang ◽  
Muhammad P. Jahan ◽  
Ajay P. Malshe
Keyword(s):  
Friction And Wear ◽  
Friction Reduction ◽  
Chemical Information ◽  
Elemental Distribution ◽  
X Ray ◽  
Lubrication Regimes ◽  
Significant Difference ◽  
Chemical States ◽  
Wear Reduction ◽  
Friction Polymer

MoS2 multi-component nanolubrication system showed significant friction and wear reduction (more than 30% in friction reduction and 50% in wear reduction) in sliding steel surfaces, especially under mixed and boundary lubrication conditions [1–3]. It is believed that the formation of tribofilms in MoS2 multi-component nanolubrication system under different lubrication regimes is the primary reason for reduced friction and wear. To investigate the in-depth science of the tribo-chemical interface formed by MoS2 multicomponent nanolubrication system, it is necessary to study the chemical states of tribofilm during its evolution (generation ↔ regeneration) process at tribo-interfaces. Tribofilms from various lubrication regimes were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), Raman microscope, and X-ray photoelectron spectroscopy (XPS) techniques to study the morphology, chemical composition, elemental distribution, and chemical bonding of tribo-chemical surface, respectively. Besides the evolution process, the characterization of tribofilms also reveals the possibility of forming new meta-stable phases (chemical compounds) after tribological testing. Patchy tribofilms and progressive tribofilms have been observed from the SEM analysis and the EDX results showed existence of Mo-S-P as the composition of tribo-chemical films. The Raman spectroscopy analysis of tribofilms showed significant difference (such as formation of poly-molybdates) in chemical information of nanolubricants and tribofilms, which is an indication of the formation of friction polymer [4–5]. Additionally, phosphates and oxides, acting as components of surface protecting layer of tribofilms, have been found on surface by XPS technique. Moreover, MoS2 nanoparticles are found to navigate into surface asperities to protect the contacting surfaces. The results (information about the chemical states of the tribofilm) obtained from different characterization techniques can be used to explain the mechanism of friction and wear reduction associated with MoS2 multi-component nanolubrication system that has been reported in the literature.

Effects of Vanadium Oxide Nanoparticles on Friction and Wear Reduction

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Wei Dai ◽  
Kyungjun Lee ◽  
Alexander M. Sinyukov ◽  
Hong Liang
Keyword(s):  
Friction And Wear ◽  
Hydrodynamic Lubrication ◽  
Tribological Performance ◽  
Friction Reduction ◽  
Tribochemical Reaction ◽  
Base Oil ◽  
Lubrication Regimes ◽  
Wear Reduction ◽  
Light Mineral ◽  
Effective Additive

In this research, rheological and tribological performance of additive V2O5 nanoparticles in a light mineral oil has been investigated. For rheological performance, the addition of 0.2 wt. % V2O5 could reduce the viscosity of the base oil for 6%. Considering the overall friction reduction in boundary, mixed, and hydrodynamic lubrication regimes, that with 0.1 wt. % V2O5 exhibited the best effect. Friction coefficient of base oil could be reduced by 33%. In terms of wear, the addition of 0.2 wt. % V2O5 showed the lowest wear rate, which is 44% reduction compared to base oil. Through Raman spectrum and energy dispersive spectroscopy (EDS) analysis, it was found that V2O5 involved tribochemical reaction during rubbing. Vanadium intermetallic alloy (V–Fe–Cr) was found to enhance the antiwear performance. This research revealed that V2O5 nanoparticles could be an effective additive to improve tribological performance.

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.

scholarly journals In-Depth Characterization of Secondary Phases in Cu2ZnSnS4 Film and Its Application to Solar Cells

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 855 ◽  
Author(s):  
Xianfeng Zhang ◽  
Hongde Wu ◽  
Engang Fu ◽  
Yuehui Wang
Keyword(s):  
Solar Cell ◽  
Conversion Efficiency ◽  
Photoelectron Spectroscopy ◽  
Czts Film ◽  
Elemental Distribution ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical States ◽  
Czts Thin Films

Secondary phases are common in Cu2ZnSnS4 (CZTS) thin films, which can be fatal to the performance of solar cell devices fabricated from this material. They are difficult to detect by X-Ray diffraction (XRD) because of the weak peak in spectra compared with the CZTS layer. Herein, it was found that in-depth elemental distribution by a secondary ion mass spectroscopy method illustrated uniform film composition in the bulk with slight fluctuation between different grains. X-ray photoelectron spectroscopy (XPS) measurement was conducted after sputtering the layer with different depths. An Auger electron spectrum with Auger parameter were used to check the chemical states of elements and examine the distribution of secondary phases in the CZTS films. Secondary phases of CuS, ZnS and SnS were detected at the surface of the CZTS film within a 50-nm thickness while no secondary phases were discovered in the bulk. The solar cell fabricated with the as-grown CZTS films showed a conversion efficiency of 2.1% (Voc: 514.3 mV, Jsc: 10.4 mA/cm2, FF: 39.3%) with an area of 0.2 cm2 under a 100 mW/cm2 illumination. After a 50-nm sputtering on the CZTS film, the conversion efficiency of the solar cell was improved to 6.2% (Voc: 634.0 mV, Jsc: 17.3 mA/cm2, FF: 56.9%).

Tribological Study of Vegetable Oil Based Lubricants - A Review

2019 ◽  
Vol 895 ◽  
pp. 212-217
Author(s):  
Deepak ◽  
T.P. Jeevan ◽  
S.R. Jayaram
Keyword(s):  
Vegetable Oils ◽  
Metal Forming ◽  
Friction And Wear ◽  
Metal Cutting ◽  
Tribological Behavior ◽  
Friction Reduction ◽  
Wear Performance ◽  
Environment Friendly ◽  
Petroleum Resources ◽  
Wear Reduction

Lubricants have a very crucial role in machinery industry for friction reduction and wear reduction between two relatively moving parts. The current study enlightens the works from various authors on evaluating the tribological behavior of environment friendly vegetable based oils as emerging biodegradable lubricants. The influences of the vegetable oils on friction and wear performance using different Tribometers were reported. The review focuses efforts on the development and commercialization of these vegetable based oils as industrial lubricants for manufacturing industries, mainly, metal forming and metal cutting. The review reveals that, many vegetable oils can be used as industrial lubricant, due to their exemplary attributes in terms of friction and wear reduction, which would help to decrease the universal demand of commercial lubricants which are based on petroleum resources to a great extent.

scholarly journals Correlative optical photothermal infrared and X-ray fluorescence for chemical imaging of trace elements and relevant molecular structures directly in neurons

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Nadja Gustavsson ◽  
Agnes Paulus ◽  
Isak Martinsson ◽  
Anders Engdahl ◽  
Kadda Medjoubi ◽  
...  
Keyword(s):  
Trace Elements ◽  
Amyloid Β ◽  
Neuronal Cell ◽  
Chemical Imaging ◽  
Molecular Structures ◽  
Chemical Information ◽  
Electromagnetic Spectrum ◽  
Elemental Distribution ◽  
Amyloid Β Protein ◽  
X Ray

AbstractAlzheimer’s disease (AD) is the most common cause of dementia, costing about 1% of the global economy. Failures of clinical trials targeting amyloid-β protein (Aβ), a key trigger of AD, have been explained by drug inefficiency regardless of the mechanisms of amyloid neurotoxicity, which are very difficult to address by available technologies. Here, we combine two imaging modalities that stand at opposite ends of the electromagnetic spectrum, and therefore, can be used as complementary tools to assess structural and chemical information directly in a single neuron. Combining label-free super-resolution microspectroscopy for sub-cellular imaging based on novel optical photothermal infrared (O-PTIR) and synchrotron-based X-ray fluorescence (S-XRF) nano-imaging techniques, we capture elemental distribution and fibrillary forms of amyloid-β proteins in the same neurons at an unprecedented resolution. Our results reveal that in primary AD-like neurons, iron clusters co-localize with elevated amyloid β-sheet structures and oxidized lipids. Overall, our O-PTIR/S-XRF results motivate using high-resolution multimodal microspectroscopic approaches to understand the role of molecular structures and trace elements within a single neuronal cell.

scholarly journals Selected Methods and Applications of Anti-Friction and Anti-Wear Surface Texturing

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3227
Author(s):  
Slawomir Wos ◽  
Waldemar Koszela ◽  
Pawel Pawlus
Keyword(s):  
Energy Consumption ◽  
Wear Surface ◽  
Lower Energy ◽  
Friction And Wear ◽  
Surface Texturing ◽  
Friction Reduction ◽  
Energy Losses ◽  
Surface Textures ◽  
Abrasive Jet Machining ◽  
Wear Reduction

The constant development of environmental protection causes the necessity to increase the efficiency of machines. By increasing the efficiency of machines, energy losses can be limited, leading to lower energy consumption. Friction reduction leads to an increase in efficiency and a decrease in wear. In this paper, selected surface texturing methods, such as burnishing and abrasive jet machining, with their limitations are presented. Thanks to those processes, various surface textures can be obtained. Examples of applications of these methods for friction and wear reduction are shown.

scholarly journals Role of Eco-Friendly Bio-Based Graphene-Oil Nanofluids on Friction Reduction for Wind Turbine Application

2021 ◽  
Vol 943 (1) ◽  
pp. 012012
Author(s):  
K P Ng ◽  
K W Liew ◽  
E Lim
Keyword(s):  
Wind Turbine ◽  
Power Efficiency ◽  
Carbon Emission ◽  
Friction And Wear ◽  
Fossil Fuel ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Friction Reduction ◽  
High Oleic ◽  
Wear Reduction

Abstract Sustainable energy such as wind turbine is known as a green technology that minimize the carbon emission into environment. However, unwanted friction and wear in journal bearing of a wind turbine’s gearbox leads to reduction of power efficiency and increase the reliance onto fossil-fuel powered electricity. Lubricating oils are used in journal bearing to provide the hydrodynamic lubrication film. However, commercially available lubricants are petroleum-based, which are non-replenishable and toxic. Thus, the bio-degradable vegetable oil, high oleic palm oil-based methyl ester (high oleic POME) was used as a base oil synthesized with graphene nanoplatelets (GNP), multi-walled carbon nanotubes (MWCNT) and nanostructured graphite (NSG), respectively, to enhance the friction and wear reduction. The tribological performance of each type of bio-based graphene-oil nanofluid was studied using pin-on-ring tribo-tester. It is concluded that NSG in high oleic POME shows 52.03% friction coefficient reduction and 59.27% pin specimen weight loss reduction. With this significant friction and wear reduction, power efficiency of wind turbine will be improved significantly. Thus, the reliance of society depending on fossil-fuel powered electricity can be reduced and minimize the carbon emission into the environment.

Preparation of ZrO2 in SiC coating via hydrothermal method and sintering process onto carbon/carbon composite

2021 ◽  
Vol 11 (12) ◽  
pp. 1997-2003
Author(s):  
Zu-Li Mao ◽  
Li Yang ◽  
Jie Wu
Keyword(s):  
Hydrothermal Method ◽  
Photoelectron Spectroscopy ◽  
Carbon Composite ◽  
Elemental Distribution ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Carbon Phase ◽  
X Ray ◽  
Sem Image ◽  
Chemical States

To reduce the defects in SiC coating, a SiC/ZrO2 composite is prepared and coated onto carbon/carbon composite via hydrothermal method and sintering process. The microstructure, surface morphology, chemical states, and elemental distribution of SiC/ZrO2 coating are analysed with X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). In addition, we analyze the tribological behavior of the SiC and SiC/SiC/ZrO2 coatings and the related microstructure. The results show that SiC/ZrO2 coating is composed of SiC phase, ZrO2 phase, carbon phase, and SiO2 phase. EDS results show that Si, C, O, and Zr elements are present in the SiC/ZrO2 coating. Moreover, XPS results show the presence of SiC, ZrO2, and SiO2. According to the SEM image, the coating is dense except for some observable cracks. Notably, specimens with the SiC/ZrO2 coating have smaller, more stable friction coefficients and less weight loss than specimens with the SiC-only coating. The formation of ZrO2 strengthens the SiC coating, while the SiO2 formed in the coating acts as a lubricant and reduces the friction coefficient of the coating.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

X-ray microprobe for materials science

1994 ◽  
Vol 52 ◽  
pp. 56-57
Author(s):  
G.E. Ice
Keyword(s):  
Crystallographic Orientation ◽  
Local Structure ◽  
Materials Science ◽  
Chemical Information ◽  
X Ray Diffraction ◽  
Ray Optics ◽  
X Ray ◽  
Novel Materials ◽  
New Information ◽  
Elemental Sensitivity

The increasing availability of synchrotron x-ray sources has stimulated the development of advanced hard x-ray (E≥5 keV) microprobes. With new x-ray optics these microprobes can achieve micron and submicron spatial resolutions. The inherent elemental and crystallographic sensitivity of an x-ray microprobe and its inherently nondestructive and penetrating nature will have important applications to materials science. For example, x-ray fluorescent microanalysis of materials can reveal elemental distributions with greater sensitivity than alternative nondestructive probes. In materials, segregation and nonuniform distributions are the rule rather than the exception. Common interfaces to whichsegregation occurs are surfaces, grain and precipitate boundaries, dislocations, and surfaces formed by defects such as vacancy and interstitial configurations. In addition to chemical information, an x-ray diffraction microprobe can reveal the local structure of a material by detecting its phase, crystallographic orientation and strain.Demonstration experiments have already exploited the penetrating nature of an x-ray microprobe and its inherent elemental sensitivity to provide new information about elemental distributions in novel materials.

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