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Journal ArticleDOI

Anti-frictional role of diamond and graphite suspended bio-oil based nano-aerosols at sliding interface of Al-SiCp and WC-6Co

01 Jan 2021-Tribology International (Elsevier)-Vol. 153, pp 106596
TL;DR: In this article, the authors investigated tribo-phenomena at sliding interface of Al2124-17SiCp disc and WC-6Co pin and explored suitability of nano-oil aerosols as lubricants.
About: This article is published in Tribology International.The article was published on 2021-01-01. It has received 7 citations till now. The article focuses on the topics: Graphite & Diamond.
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Journal ArticleDOI
Zhishan Luo1, Qiang Wan1, Zhiyang Yu1, Sen Lin1, Zailai Xie1, Xinchen Wang1 
TL;DR: A photo-induced surface fluorination strategy facilitates innovative breakthroughs on the carbocatalysis for the oxidative dehydrogenation of other arenes as discussed by the authors, which has a fabulous performance with ethylbenzene conversion reaching 70% as well as styrene yields of 63% and selectivity over 90% on a stream of 400
Abstract: Styrene is one of the most important industrial monomers and is traditionally synthesized via the dehydrogenation of ethylbenzene. Here, we report a photo-induced fluorination technique to generate an oxidative dehydrogenation catalyst through the controlled grafting of fluorine atoms on nanodiamonds. The obtained catalyst has a fabulous performance with ethylbenzene conversion reaching 70% as well as styrene yields of 63% and selectivity over 90% on a stream of 400 °C, which outperforms other equivalent benchmarks as well as the industrial K−Fe catalysts (with a styrene yield of 50% even at a much higher temperature of ca. 600 °C). Moreover, the yield of styrene remains above 50% after a 500 h test. Experimental characterizations and density functional theory calculations reveal that the fluorine functionalization not only promotes the conversion of sp3 to sp2 carbon to generate graphitic layers but also stimulates and increases the active sites (ketonic C=O). This photo-induced surface fluorination strategy facilitates innovative breakthroughs on the carbocatalysis for the oxidative dehydrogenation of other arenes. Styrene is one of the most important industrial monomers and is traditionally synthesized via the dehydrogenation of ethylbenzene. Here, the authors report a photo-induced fluorination technique to generate an oxidative dehydrogenation catalyst through the controlled grafting of fluorine atoms on nanodiamonds.

7 citations

Journal ArticleDOI
TL;DR: In this article , a numerical model that combines computational fluid dynamics (CFD) and discrete phase model (DPM) is presented to simulate droplet transport process for dynamic milling and one-tooth milling by flow field distribution and droplet characteristics.
Abstract: The infiltration and cooling effect of lubricant droplets in the cutting zone largely depend on setting minimum quantity lubricant (MQL) system parameters appropriately. The study determines the optimal spray angle and spray distance relying on the geometric position relationship between the nozzle and the overall cutting zone. A numerical model that combines computational fluid dynamics (CFD) and discrete phase model (DPM) is presented to simulate droplet transport process for dynamic milling and one-tooth milling by flow field distribution and droplet characteristics. The influences of different spray distances and spray angles on the infiltration process and cutting tool temperature are analyzed. The experiments aimed at verifying the results of the analysis are conducted by measuring cutting force, cutting temperature, surface roughness, surface microtopography and tool wear. The result indicates that the spray distance has a significant impact on the jet divergence, and insufficient lubrication or excessive lubrication is effectively avoided with the optimal cutting distance. Spraying in the direction of cutting-out promotes the accessibility of the lubricant and greater concentration of droplets in the cutting zone, especially later in the cutting process, which results in increased infiltration, reduced friction, and improved heat dissipation. Moreover, experiments demonstate that the optimal state of jetting in the direction of cutting-out is 46 °C lower than that of dry cutting, the surface roughness is reduced by 19.8%, and the wear amount is reduced by roughly 34%. This study has a better understanding of the setting of spray distance and spray angle in MQL milling and the development of equipment, which provides theoretical guidance for the optimization of MQL system parameters in practical applications.

3 citations

Journal ArticleDOI
TL;DR: In this article , the additive manufacturing techniques, which include point-by-point material merging, full melting, and solidification of powder particles, provide potential unique braves and advantages with nanometal powders.
Abstract: Additive manufacturing techniques (AMTs) evolved quickly from simple prototype options to promising additive manufacturing techniques. The additive technologies, which include point-by-point material merging, full melting, and solidification of powder particles, provide potential unique braves and advantages with nanometal powders. In the fabrication of A356 aluminium alloy-based hybrid metal matrix nanocomposites, graphite (Gr), iron oxide (Fe3O4), and boron carbide (B4C) are used as nanoreinforcement. Famous AMTs like selective laser melting have created A356 hybrid nanocomposites (SLM). The ingot was made out of a cylindrical slot measuring 14 × 100 mm. The percentages 2%, 4%, and 6% are added to the reinforcements Gr, Fe3O4, and B4C. Microtensile and microhardness tests were used to determine the outcome of the reinforcement. Microtensile and microhardness parameters are assessed using microtensile test equipment and a Vickers hardness tester, with the specimen prepared in accordance with ASTM standards. A356 with 2, 4, and 6% reinforcing has a Vickers Hardness Number (VHN) of 144, 163, and 188, respectively. As the boron carbide reinforcement is increased, the load value of graphite and iron oxide (2, 4, and 6%) rises. The greatest ultimate tensile strengths are 260.10, 290.06, and 325.43 N/mm2, respectively. The bonding structure of nanocomposites is assessed using an OM, and then, microtensile specimens are assessed using a SEM. As a result of the superior effect of the diverse reinforcements Gr, Fe3O4, and B4C, more increased tensile and hardness qualities have been attained.

2 citations

Journal ArticleDOI
30 Apr 2022-Friction
TL;DR: In this paper , a comprehensive insight into the tribological behavior of a variety of 2D QDs together with the associated mechanism is reviewed in detail, including rolling effect, self-mending performance, polishing effect, tribofilm formation, nanostructure transfer and synergistic effects.
Abstract: Abstract Very recently, two-dimensional quantum dots (2D QDs) have been pioneeringly investigated as lubricant additives, which exhibit superior friction-reducing and wear resistance. Compared with 2D nanoparticles, 2D QDs possess small size (∼10 nm) and abundant active groups. These distinguished advantages enable them to quickly disperse into common lube mediums and maintain long-term storage stability. The good dispersion stability of 2D QDs not only effectively improves their embedding capacity, but also enables continuous supplements of lubricants during the sliding process. Therefore, 2D QDs are attracting increasing research interest as efficient lubricants with desirable service life. In this review, we focus on the latest studies of 2D QDs as liquid lubricant additives (both in polar and nonpolar mediums), self-lubricating solid coatings and gels, etc. Various advanced strategies for synthesis and modification of 2D QDs are summarized. A comprehensive insight into the tribological behavior of a variety of 2D QDs together with the associated mechanism is reviewed in detail. The superior lubricating performances of 2D QDs are attributed to various mechanisms, including rolling effect, self-mending performance, polishing effect, tribofilm formation, nanostructure transfer and synergistic effects, etc. Strategies for friction modulation of 2D QDs, including internal factors (surface modification, elemental doping) and extrinsic factors (counter surfaces, test conditions) are discussed, special attentions for achieving intelligent tribology toward superlubricity and bio-engineering, are also included. Finally, the future challenges and research directions regarding QDs as lubricants conforming to the concept of “green tribology” toward a sustainable society are discussed.

2 citations

Journal ArticleDOI
TL;DR: In this paper , nano-multi-powder particles, 5 and 10 wt.% boron carbide (B4C) and graphite (Gr) are utilized as a reinforcement, and aluminium LM 25 alloy is used as a matrix.
Abstract: The current investigation, nano-multi-powder particles, 5 and 10 wt.% boron carbide (B4C) and graphite (Gr) are utilized as a reinforcement, and aluminium LM 25 alloy is used as a matrix. These hybrid nanocomposites were fabricated by a novel additive manufacturing method—selective laser melting. The specimen was carried out in a cylindrical size having 2 circular slots of dimension 14 and length 50 mm. The diverse SLM specimens focused on tribological properties of impact, creep, tensile, and hardness were carried out for the three specimens with same weight percentage of nanoparticles. The consequence of the reinforcement has been performed through microtensile and microhardness tests. The microtensile and microhardness properties are evaluated by microtensile test machine and Vickers hardness tester, and the specimen has been prepared as per ASTM E8 and ASTM E18 standards. Microtensile strength and hardness were augmented by the addition of B4C and graphite nanoparticles. The tensile strength and hardness values are 668.93 MPa and 739.16 MPa, and 193VHN and 206.79VHN, respectively. The result of the microstructure study shows homogeneous dispersion of B4Cnp-Grnp in the matrix material of the LM25 alloy. The FESEM image results of the ruined surface illustrate the addition performance of ductile fracture, brittle fracture, and ploughing of reinforced material. The consequences of the research enhanced tensile and hardness properties of composite with reinforcement added.

1 citations

References
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Book
15 Mar 1960
TL;DR: In this paper, the authors describe typical cutting operations, including: Elastic Behaviour Plastic Behaviour Fracture Dynamometry Shear Strain in Cutting Shear Stress in Cutting Friction Wear and Tool Life Cutting Temperatures Cutting Fields Tool Materials Work Material Considerations Complex Tools Surface Integrity Chip Control Optimisation Modeling of Chip Formation Precision Engineering Unusual Applications of the Metal Cutting Process
Abstract: Table of Contents Preface Symbols Introduction Typical Cutting Operations Mechanics of Steady State Elastic Behaviour Plastic Behaviour Fracture Dynamometry Shear Strain in Cutting Shear Stress in Cutting Friction Wear and Tool Life Cutting Temperatures Cutting Fields Tool Materials Work Material Considerations Complex Tools Surface Integrity Chip Control Optimisation Modeling of Chip Formation Precision Engineering Unusual Applications of the Metal Cutting Process

2,229 citations

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TL;DR: In this paper, a detailed analysis and adaptation of cutting parameters, cutting tools, machine tools and the production environment is mandatory to ensure an efficient process and successfully enable dry machining.

812 citations

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TL;DR: In this paper, the basic mechanism of vegetable oil autoxidation is presented, along with methods used to monitor and analyse the products of oxidation, and the potential impact of such oxidation products on lubrication performance is discussed.

641 citations

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TL;DR: In this paper, the authors provide a comprehensive overview of various lubrication aspects of a typical powertrain system including the engine, transmission, driveline, and other components, as well as the integration of these lubrication and surface engineering concepts into a unified automotive power-train system.

577 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the application of vegetable oils as potential metal working fluids is presented. But, most of the contributions are directed to develop and commercialise the cutting fluids based on vegetable oils.

398 citations