Nanomaterials in Superlubricity

Zhai, Wenzheng; Zhou, Kun

doi:10.1002/adfm.201806395

Cited by 185 publications

(97 citation statements)

References 136 publications

(181 reference statements)

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“…Fretting wear is a wear phenomenon caused by the relative oscillation of small displacement amplitude between two contact interfaces in tangential motion [62][63][64][65][66]. The PBF technology has been widely used in the medical field, mainly in the manufacture of artificial joints, artificial bones and so on.…”

Section: Fretting Wearmentioning

confidence: 99%

Wear Performance of Metal Materials Fabricated by Powder Bed Fusion: A Literature Review

Qin

Lan

et al. 2020

Metals

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Powder Bed Fusion (PBF) is an additive manufacturing technology used to produce metal-based materials. PBF materials have a unique microstructure as a result from repeated and sharp heating/cooling cycles. Many researches have been carried out on relations between processing parameters of the PBF technology, obtained microstructures and mechanical properties. However, there are few studies on the tribological properties of PBF materials at various contact conditions. This article describes previous and recent studies related to the friction performance. This is a critical aspect if PBF materials are applied to friction pair components. This paper discusses wear rates and wear mechanisms of PBF materials under dry friction, boundary lubrication and micro-motion conditions. PBF materials have higher hardness due to fine grains. PBF materials have a higher wear resistance than traditional materials due to their solid solution strengthening. In addition, hard particles on the surface of PBF components can effectively reduce wear. The reasonable combination of process parameters can effectively improve the density of parts and thus further improve the wear resistance. This review paper summarized the wear behavior of PBF materials, the wear mechanism of metal materials from dry friction to different lubrication conditions, and the wear behavior under fretting wear. This will help to control the processing parameters and material powder composition of parts, so as to achieve the required material properties of parts and further improve the wear performance.

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Section: Fretting Wearmentioning

confidence: 99%

Wear Performance of Metal Materials Fabricated by Powder Bed Fusion: A Literature Review

Qin

Lan

et al. 2020

Metals

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“…Nanomaterials, due to their high chemical stability and small size, are being preferred as lubricant additives over the conventional organics [4][5][6][7]. The small size of nanomaterials triggers fast tribological action at the surface while their chemical stability minimizes emissions [8][9][10]. Wide varieties of nanoparticles, like metal oxides, metal sulphides, metal halides, and carbon-based materials, have been reported in the literature as lubricant additives [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide

et al. 2020

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Zirconia and 10%, 20%, and 30% cerium-doped zirconia nanoparticles (ZCO), ZCO-1, ZCO-2, and ZCO-3, respectively, were prepared using auto-combustion method. Binary nanohybrids, ZrO2@rGO and ZCO-2@rGO (rGO = reduced graphene oxide), and ternary nanohybrids, ZrO2@rGO@MoS2 and ZCO-2@rGO@MoS2, have been prepared with an anticipation of a fruitful synergic effect of rGO, MoS2, and cerium-doped zirconia on the tribo-activity. Tribo-activity of these additives in paraffin oil (PO) has been assessed by a four-ball lubricant tester at the optimized concentration, 0.125% w/v. The tribo-performance follows the order: ZCO-2@rGO@MoS2 > ZrO2@rGO@MoS2 > ZCO-2@rGO > ZrO2@rGO > MoS2 > ZrO2 > rGO > PO. The nanoparticles acting as spacers control restacking of the nanosheets provided structural augmentation while nanosheets, in turn, prevent agglomeration of the nanoparticles. Doped nanoparticles upgraded the activity by forming defects. Thus, the results acknowledge the synergic effect of cerium-doped zirconia and lamellar nanosheets of rGO and MoS2. There is noncovalent interaction among all the individuals. Analysis of the morphological features of wear-track carried out by scanning electron microscopy (SEM) and atomic force microscopy (AFM) in PO and its formulations with various additives is consistent with the above sequence. The energy dispersive X-ray (EDX) spectrum of ZCO-2@rGO@MoS2 indicates the existence of zirconium, cerium, molybdenum, and sulfur on the wear-track, confirming, thereby, the active role played by these elements during tribofilm formation. The X-ray photoelectron spectroscopy (XPS) studies of worn surface reveal that the tribofilm is made up of rGO, zirconia, ceria, and MoS2 along with Fe2O3, MoO3, and SO42− as the outcome of the tribo-chemical reaction.

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“…Even a modest 20% reduction of friction can substantially contribute to energy savings and reduce carbon dioxide emission . The removal of friction is known as superlubricity, which is highly desirable for energy saving, environmental benefits and increasing the lifetime of mechanical components . Superlubricity is defined such that the friction coefficient, µ is less than 0.01. µ is calculated

μ = F_{1} / F_{n}

where the F l and F n are lateral and normal forces, respectively.…”

Section: Introductionmentioning

confidence: 99%

Macroscale Superlubricity Enabled by Graphene‐Coated Surfaces

Zhang

Huang

et al. 2020

Advanced Science

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Friction and wear remain the primary modes for energy dissipation in moving mechanical components. Superlubricity is highly desirable for energy saving and environmental benefits. Macroscale superlubricity was previously performed under special environments or on curved nanoscale surfaces. Nevertheless, macroscale superlubricity has not yet been demonstrated under ambient conditions on macroscale surfaces, except in humid air produced by purging water vapor into a tribometer chamber. In this study, a tribological system is fabricated using a graphene‐coated plate (GCP), graphene‐coated microsphere (GCS), and graphene‐coated ball (GCB). The friction coefficient of 0.006 is achieved in air under 35 mN at a sliding speed of 0.2 mm s−1 for 1200 s in the developed GCB/GCS/GCP system. To the best of the knowledge, for the first time, macroscale superlubricity on macroscale surfaces under ambient conditions is reported. The mechanism of macroscale superlubricity is due to the combination of exfoliated graphene flakes and the swinging and sliding of the GCS, which is demonstrated by the experimental measurements, ab initio, and molecular dynamics simulations. These findings help to bridge macroscale superlubricity to real world applications, potentially dramatically contributing to energy savings and reducing the emission of carbon dioxide to the environment.

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Nanomaterials in Superlubricity

Cited by 185 publications

References 136 publications

Wear Performance of Metal Materials Fabricated by Powder Bed Fusion: A Literature Review

Wear Performance of Metal Materials Fabricated by Powder Bed Fusion: A Literature Review

Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide

Macroscale Superlubricity Enabled by Graphene‐Coated Surfaces

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