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21 pages, 3428 KiB

Open AccessArticle

Machinability Assessment of Hybrid Nano Cutting Oil for Minimum Quantity Lubrication (MQL) in Hard Turning of 90CrSi Steel

by Tran Bao Ngoc, Tran Minh Duc, Ngo Minh Tuan, Vu Lai Hoang and Tran The Long

Lubricants 2023, 11(2), 54; https://doi.org/10.3390/lubricants11020054 - 31 Jan 2023

Cited by 8 | Viewed by 1614

Abstract

Friction and very high temperature are still the major challenges in hard machining technology and they greatly affect cutting efficiency. The application of the MQL (minimum quantity lubrication) method, using nanoparticles in order to improve the cooling lubrication performance of the base cutting [...] Read more.

Friction and very high temperature are still the major challenges in hard machining technology and they greatly affect cutting efficiency. The application of the MQL (minimum quantity lubrication) method, using nanoparticles in order to improve the cooling lubrication performance of the base cutting oil, has proven to be a promising solution. Hence, this work aimed to investigate the effectiveness of Al₂O₃/MoS₂ hybrid nanofluid and Al₂O₃ and MoS₂ mono nanofluids in the hard turning of 90CrSi steel (60–62 HRC) under an MQL environment. The Box-Behnken experimental design was used for three input variables, including nanoparticle concentration, air pressure, and air flow rate. Their influences on surface roughness and cutting forces were studied. According to the obtained results, it was shown that the application of hybrid nano cutting oils in MQL contributes to achieving better hard machining performance than the use of mono nanofluids. In particular, a lower cutting temperature is reported and the values of surface roughness R_a, back force F_p, and cutting force F_c were smaller and more stable under Al₂O₃/MoS₂ hybrid nanofluid MQL than those under Al₂O₃ and MoS₂ mono nanofluid MQL due to an improvement in cooling lubrication characteristics. Thus, this work provides a novel approach to study hybrid nanofluids for MQL hard machining. Full article

(This article belongs to the Special Issue Tribological Applications of Nano & Submicro Structured Materials)

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14 pages, 5974 KiB

Open AccessArticle

Polyaniline Nanoparticles: A Novel Additive for Augmenting Thermal Conductivity and Tribo-Properties of Mineral Oil and Commercial Engine Oil

by Vinay Saini and Jayashree Bijwe

Lubricants 2022, 10(11), 300; https://doi.org/10.3390/lubricants10110300 - 09 Nov 2022

Cited by 4 | Viewed by 2226

Abstract

The present work demonstrates the novel composition of nanoparticles (NPs) of polyaniline (PANI) solo and, in combination with particles of polytetrafluoroethylene (PTFE) ~230 nm, as a powerful additive (antiwear-AWA and extreme-pressure additive EPA) in lubricating oils. The concentration of PANI NPs varied from [...] Read more.

The present work demonstrates the novel composition of nanoparticles (NPs) of polyaniline (PANI) solo and, in combination with particles of polytetrafluoroethylene (PTFE) ~230 nm, as a powerful additive (antiwear-AWA and extreme-pressure additive EPA) in lubricating oils. The concentration of PANI NPs varied from 1–4 wt.% in a base oil and commercial 5W30 engine oil. The tribo-performance was evaluated on a four-ball tester. The PANI-based oils significantly enhanced the load-bearing ability, and 3 wt.% of PANI NPs led to enhancement in EP properties by 220% in a base oil and 58% in engine oil. Additionally, hybrid combinations of NPs of PTFE with PANI in base oil were prepared by mixing in a ratio of 3:1 and 2:1 and were explored for possible tribo-synergism in EP properties. The hybrid nano-oils led to the highest reported ~ 535% enhancement in the load-carrying capacity of mineral oil. The lubrication mechanisms for enhanced tribo performance were linked with studies on a scanning electron microscope, an energy-dispersive X-ray analyzer, and with the use of Raman spectroscopy. Full article

(This article belongs to the Special Issue Tribological Applications of Nano & Submicro Structured Materials)

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18 pages, 3929 KiB

Open AccessArticle

Prediction of Tribological Properties of Alumina-Coated, Silver-Reinforced Copper Nanocomposites Using Long Short-Term Model Combined with Golden Jackal Optimization

by Ismail R. Najjar, Ayman M. Sadoun, Adel Fathy, Ahmed W. Abdallah, Mohamed Abd Elaziz and Marwa Elmahdy

Lubricants 2022, 10(11), 277; https://doi.org/10.3390/lubricants10110277 - 24 Oct 2022

Cited by 46 | Viewed by 1878

Abstract

In this paper, we present a newly modified machine learning model that employs a long short-term memory (LSTM) neural network model with the golden jackal optimization (GJO) algorithm to predict the tribological performance of Cu–Al₂O₃ nanocomposites. The modified model was [...] Read more.

In this paper, we present a newly modified machine learning model that employs a long short-term memory (LSTM) neural network model with the golden jackal optimization (GJO) algorithm to predict the tribological performance of Cu–Al₂O₃ nanocomposites. The modified model was applied to predict the wear rates and coefficient of friction of Cu–Al₂O₃ nanocomposites that were developed in this study. Electroless coating of Al₂O₃ nanoparticles with Ag was performed to improve the wettability followed by ball milling and compaction to consolidate the composites. The microstructural, mechanical, and wear properties of the produced composites with different Al₂O₃ content were characterized. The wear rates and coefficient of friction were evaluated using sliding wear tests at different loads and speeds. From a materials point of view, the manufactured composites with 10% Al₂O₃ content showed huge enhancement in hardness and wear rates compared to pure copper, reaching 170% and 65%, respectively. The improvement of the properties was due to the excellent mechanical properties of Al₂O₃, grain refinement, and dislocation movement impedance. The developed model using the LSTM-GJO algorithm showed excellent predictability of the wear rate and coefficient of friction for all the considered composites. Full article

(This article belongs to the Special Issue Tribological Applications of Nano & Submicro Structured Materials)

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13 pages, 9472 KiB

Open AccessArticle

Experimental Investigation of Tribological Properties of Two Fully Formulated Engine Oils with Additional Nanoscale Spherical Zirconia Particles

by Rajmund Kuti, Ádám István Szabó and Álmos Dávid Tóth

Lubricants 2022, 10(10), 246; https://doi.org/10.3390/lubricants10100246 - 30 Sep 2022

Cited by 2 | Viewed by 1611

Abstract

Decreasing harmful emissions of vehicle engines is becoming more and more challenging due to stricter standards. A possible solution is to improve the tribological attributes of lubricants, which can be achieved through the application of appropriate additives. According to preliminary studies conducted by [...] Read more.

Decreasing harmful emissions of vehicle engines is becoming more and more challenging due to stricter standards. A possible solution is to improve the tribological attributes of lubricants, which can be achieved through the application of appropriate additives. According to preliminary studies conducted by the authors, ZrO₂ (zirconium-dioxide) nano-sized ceramic particles as lubricant additives have overwhelmingly positive tribological attributes in the presence of non-metallic superficial materials. Additive concentration, as well as cross-effects with other additives were investigated in order to determine a formulation resulting in optimal tribological attributes. In this paper, the experimental investigation of ZrO₂ nano-ceramic powder as a lubricant additive is presented. The tribological performance of individually samples were experimentally investigated on a ball-on-disc translational tribometer. The experiments revealed an optimal additive content of 0.3 wt%. Increasing the quantity of additives further ruined friction and wear properties of the examined tribological system. Full article

(This article belongs to the Special Issue Tribological Applications of Nano & Submicro Structured Materials)

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14 pages, 3168 KiB

Open AccessArticle

Investigation of the Applicability of Y₂O₃–ZrO₂ Spherical Nanoparticles as Tribological Lubricant Additives

by Ádám I. Szabó, Álmos D. Tóth, Máté Zs. Leskó and Hajnalka Hargitai

Lubricants 2022, 10(7), 152; https://doi.org/10.3390/lubricants10070152 - 12 Jul 2022

Cited by 7 | Viewed by 1533

Abstract

Long-term environmental goals will motivate the automotive industry, component suppliers, and lubricating oil developers to reduce the friction of their tribosystems to improve overall efficiency and wear for increased component lifetime. Nanoscale ceramic particles have been shown to form a protective layer on [...] Read more.

Long-term environmental goals will motivate the automotive industry, component suppliers, and lubricating oil developers to reduce the friction of their tribosystems to improve overall efficiency and wear for increased component lifetime. Nanoscale ceramic particles have been shown to form a protective layer on components’ surface that reduces wear rate with its high hardness and chemical resistance. One such ceramic is yttria (Y₂O₃), which has an excellent anti-wear effect, but due to its rarity it would be extremely expensive to produce engine lubricant made from it. Therefore, part of the yttria is replaced by zirconia (ZrO₂) with similar physical properties. The study presents the result of the experimental tribological investigation of nanosized yttria–zirconia ceramic mixture as an engine lubricant additive. Yttria-stabilized zirconia (YSZ) nanoparticle was used as the basis for the ratio of the ceramic mixture, so that the weight ratio of yttria–zirconia in the resulting mixture was determined to be 11:69. After the evaluation of the ball-on-disc tribological measurements, it can be stated that the optimal concentration was 0.4 wt%, which reduced the wear diameter by 30% and the wear volume by 90% at the same coefficient of friction. High-resolution SEM analysis showed a significant amount of zirconia on the surface, but no yttria was found. Full article

(This article belongs to the Special Issue Tribological Applications of Nano & Submicro Structured Materials)

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12 pages, 3495 KiB

Open AccessArticle

Polymeric Coatings for Skutterudite-Based Thermoelectric Materials

by Witold Brostow, IKang Chen and Haley E. Hagg Lobland

Lubricants 2022, 10(4), 72; https://doi.org/10.3390/lubricants10040072 - 18 Apr 2022

Viewed by 1866

Abstract

Thermoelectric (TE) devices have short service lives. These materials undergo thermal degradation at elevated temperatures by processes such as oxidation or sublimation. Our substrates were skutterudite-based TE materials. We covered their surfaces with a liquid high-temperature polymer (HTP)—crosslinked after the deposition, what converted [...] Read more.

Thermoelectric (TE) devices have short service lives. These materials undergo thermal degradation at elevated temperatures by processes such as oxidation or sublimation. Our substrates were skutterudite-based TE materials. We covered their surfaces with a liquid high-temperature polymer (HTP)—crosslinked after the deposition, what converted those surfaces into solid coatings. Sintering was performed at 250 °C for times of up to 48 h on both uncoated (control) and HTP-coated samples. The changes caused by thermal degradation were evaluated by thermogravimetric analysis, electrical resistivity, and energy-dispersive X-ray spectroscopy, and observed by scanning electron microscopy. Significant mitigation of oxidation and sublimation of our TE materials was achieved. Full article

(This article belongs to the Special Issue Tribological Applications of Nano & Submicro Structured Materials)

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10 pages, 4402 KiB

Open AccessArticle

Wear Resistance of TiAlCrSiN Coatings Deposited by Means of the Co-Sputtering Technique

by Fredy Antonio Estupiñan, Carlos Mauricio Moreno, Jhon Jairo Olaya and Luis Carlos Ardila

Lubricants 2021, 9(6), 64; https://doi.org/10.3390/lubricants9060064 - 21 Jun 2021

Cited by 6 | Viewed by 1924

Abstract

TiAlCrSiN thin films were deposited on K20 WC–Co substrates using the co-sputtering method. The silicon content in the deposited coatings were varied by modifying the number of silicon pieces (1, 2, or 3) on the Cr target. The morphology, semi-quantitative chemical composition, and [...] Read more.

TiAlCrSiN thin films were deposited on K20 WC–Co substrates using the co-sputtering method. The silicon content in the deposited coatings were varied by modifying the number of silicon pieces (1, 2, or 3) on the Cr target. The morphology, semi-quantitative chemical composition, and microstructure were investigated using scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), and X-ray diffraction (XRD), respectively. Modified ASTM B611 abrasive wear and nano-hardness tests were used to evaluate the tribological and mechanical properties of the different coatings, respectively. The results showed that the addition of Si promotes an increased hardness and elastic modulus. Also, mass loss in wear tests decreased as Si increased, due to the growth in hardness related to the microstructural refinement produced by the blocking of sliding bands by the grain boundaries. Full article

(This article belongs to the Special Issue Tribological Applications of Nano & Submicro Structured Materials)

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Review

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12 pages, 1933 KiB

Open AccessReview

Frictional Properties of Two-Dimensional Nanomaterials as an Additive in Liquid Lubricants: Current Challenges and Potential Research Topics

by Edgar Leonardo Castellanos-Leal, Angel Osuna-Zatarain and Alejandra Garcia-Garcia

Lubricants 2023, 11(3), 137; https://doi.org/10.3390/lubricants11030137 - 14 Mar 2023

Cited by 3 | Viewed by 1550

Abstract

This paper reports on the trend of studying and applying two-dimensional materials in tribology. Two-dimensional materials have improved the ability of lubricants when used as additives to reduce wear between surfaces through the formation of protective layers by sliding on metal surfaces. The [...] Read more.

This paper reports on the trend of studying and applying two-dimensional materials in tribology. Two-dimensional materials have improved the ability of lubricants when used as additives to reduce wear between surfaces through the formation of protective layers by sliding on metal surfaces. The morphology and chemical nature of 2D materials are among the important factors that influence their dispersion in the lubricant medium and determine the final performance of the lubricant for various applications. The mentioned materials in this work are h-BN, graphene, graphene oxide, and MoS₂ as part of the transition metal dichalcogenides. The most studied material to date is graphene and its analogs, such as graphene oxide, which, under controlled conditions, can present superlubricity, with COF values less than 0.01. Some methodologies applied to modify two-dimensional materials and examples of the application and characterization of their performance in tribology are mentioned. This review also shows the benefits of using 2D nanomaterials and the synergy generated when two or more of them are combined to not only achieve superlubricity but also improve corrosion resistance and mechanical properties at the interfaces found in contact. Full article

(This article belongs to the Special Issue Tribological Applications of Nano & Submicro Structured Materials)

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24 pages, 5690 KiB

Open AccessReview

Tribological Properties of CNTs-Reinforced Nano Composite Materials

by Chika Oliver Ujah, Daramy Vandi Von Kallon and Victor Sunday Aigbodion

Lubricants 2023, 11(3), 95; https://doi.org/10.3390/lubricants11030095 - 22 Feb 2023

Cited by 10 | Viewed by 1952

Abstract

High modulus of about 1 TPa, high thermal conductivity of over 3000 W/mK, very low coefficient of thermal expansion (CTE), high electrical conductivity, self-lubricating characteristics and low density have made CNTs one of the best reinforcing materials of nano composites for advanced structural, [...] Read more.

High modulus of about 1 TPa, high thermal conductivity of over 3000 W/mK, very low coefficient of thermal expansion (CTE), high electrical conductivity, self-lubricating characteristics and low density have made CNTs one of the best reinforcing materials of nano composites for advanced structural, industrial, high strength and wear-prone applications. This is so because it has the capacity of improving the mechanical, tribological, electrical, thermal and physical properties of nanocomposites. So, this study is aimed at providing the latest discoveries on the tribological behavior of CNTs-reinforced composites. The composites reviewed included metal matrix composites (MMCs), polymer matrix composites (PMCs) and ceramic matrix composites (CMCs) reinforced with CNTs. Their tribological characteristics, uses, production challenges, conclusion and recommendations are presented. The work presented the best technique to disperse CNTs on matrices to avoid its agglomeration, since agglomeration is one of the major challenges in reinforcing with CNTs. It was discovered that ball milling destroys the outer walls of CNTs but recommended that ultrasonication and functionalization before ball milling eliminate this adverse effect of ball milling. In addition, it was discovered that addition of CNTs to composite matrices improved the wear resistance, reduced the wear volume, decreased the coefficient of friction (COF) and provided self-lubricating effect on MMCs, PMCs and CMCs. Full article

(This article belongs to the Special Issue Tribological Applications of Nano & Submicro Structured Materials)

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