scholarly journals The Indirect Tribological Role of Carbon Nanotubes Stimulating Zinc Dithiophosphate Anti-Wear Film Formation

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1330
Author(s):  
Jarosław Kałużny ◽  
Andrzej Kulczycki ◽  
Wojciech Dzięgielewski ◽  
Adam Piasecki ◽  
Bartosz Gapiński ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Metal Surface ◽  
Film Formation ◽  
Experimental Studies ◽  
Electric Energy ◽  
Base Oil ◽  
Multi Wall Carbon Nanotubes ◽  
Alpha Olefin ◽  
Dialkyl Dithiophosphates ◽  
Zinc Dithiophosphate

Experimental studies reveal that the simultaneous addition of zinc dialkyl dithiophosphates (ZDDPs) and multi-wall carbon nanotubes (MWCNTs) to a poly-alpha-olefin base oil strongly reduces wear. In this paper, it is shown that MWCNTs promote the formation of an anti-wear (AW) layer on the metal surface that is much thicker than what ZDDPs can create as a sole additive. More importantly, the nanotubes’ action is indirect, i.e., MWCNTs neither mechanically nor structurally strengthen the AW film. A new mechanism for this effect is also proposed, which is supported by detailed tribometer results, friction track 3D-topography measurements, electron diffraction spectroscopy (EDS), and Raman spectroscopy. In this mechanism, MWCNTs mediate the transfer of both thermal and electric energy released on the metal surface in the friction process. As a result, this energy penetrates more deeply into the oil volume, thus extending the spatial range of tribochemical reactions involving ZDDPs.

Measurements of the Intrinsic Thermal Conductivity of Individual Multi-Wall Carbon Nanotubes

2011 ◽  
Author(s):  
Juekuan Yang ◽  
Scott W. Waltermire ◽  
Yang Yang ◽  
Deyu Li ◽  
Yunfei Chen
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Heat Source ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Experimental Studies ◽  
Contact Thermal Resistance ◽  
Multi Wall Carbon Nanotubes ◽  
The Past ◽  
Thermal Conductivities

Thermal transport through carbon nanotubes (CNTs) attracted a lot of attention over the past decade. Several experimental studies have been carried out to determine the thermal conductivities of CNTs [1–3]. However, the measurements are based on an individual CNT sample between two suspended membranes and the results actually include both the intrinsic thermal resistance of the CNT and the contact thermal resistance between the CNT and the two suspended membranes that serve as a heat source and a heat sink. Hence, the effective thermal conductivity extracted from these measurements should be lower than the intrinsic thermal conductivities of the CNTs measured. To minimize the contact thermal resistance, electron beam induce deposition (EBID) of different metals has been used to increase the contact area between the CNT and the heat source and sink [3,4]. However, it is still not clear how effective this treatment is and to what level the effective thermal conductivity obtained after the EBID treatment reflects the intrinsic one.

Carbon Nanotubes and Onions as Lubricant Additives

2005 ◽  
Author(s):  
L. Joly-Pottuz ◽  
J. M. Martin ◽  
F. Dassenoy ◽  
B. Vacher ◽  
T. Mieno ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Tribological Properties ◽  
Inorganic Nanoparticles ◽  
Lubricant Additives ◽  
Organic Additives ◽  
Friction Modifier ◽  
Tribochemical Reaction ◽  
Base Oil ◽  
Alpha Olefin ◽  
By Products

Most of lubricant additives used as friction modifier and anti-wear agents are mainly organic compounds containing sulphur and phosphorous. Their lubrication mechanism is based on a tribochemical reaction leading to tribofilm formation but also the formation of some harmful by-products. Inorganic nanoparticles (nanotubes, fullerenes, onions...), because of their unique morphology and very small size, could be envisaged for the replacement of such organic additives. The purpose of this work is to study and compare the tribological properties of different kinds of nanoparticles added and dispersed as additives to a lubricating base oil. Here, we are particularly interested in carbon nanotubes and graphite onions which were then tested and compared. Added to a poly-alpha-olefin (PAO) base oil, all nanoparticles tested show a reduction of both friction and wear of steel counterfaces. The detailed study of the concentration effect in PAO shows that 1wt% of nanotubes is sufficient to obtain good tribological properties. A structural modification of nanoparticles during friction was clearly evidenced by analytical TEM. In the case of nanotubes, flake-like wear debris made of amorphous carbon have been observed [1].

Incorporation of Multi Wall Carbon Nanotubes into Glass-Surfaces via Laser-Treatment

2003 ◽  
Vol 772 ◽  
Author(s):  
T. Seeger ◽  
G. de la Fuente ◽  
W.K. Maser ◽  
A.M. Benito ◽  
A. Righi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Continuous Wave ◽  
Silica Surface ◽  
Multi Wall Carbon Nanotubes ◽  
Composite Formation ◽  
Multi Walled Carbon Nanotubes ◽  
Glass Surfaces ◽  
Walled Carbon Nanotubes ◽  
First Time ◽  
Scanning Electron

AbstractCarbon nanotubes (CNT) are interesting candidates for the reinforcement in robust composites and for conducting fillers in polymers due to their fascinating electronic and mechanical properties. For the first time, we report the incorporation of multi walled carbon nanotubes (MWNTs) into silica-glass surfaces by means of partial surface-melting caused by a continuous wave Nd:YAG laser. MWNTs were detected being well incorporated in the silica-surface. The composites are characterized using scanning electron microscopy (SEM) and Raman-spectroscopy. A model for the composite-formation is proposed based on heatabsorption by MWNTs and a partial melting of the silica-surface.

Study of Fibroblast and Platelet Adhesion on Multi-wall Carbon Nanotubes

2011 ◽  
Vol 26 (1) ◽  
pp. 73-77 ◽  
Author(s):  
Meng-Li ZHAO ◽  
Yu-Chen YUE ◽  
Li YUAN ◽  
De-Jun LI ◽  
Xiao-Ying LÜ ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Platelet Adhesion ◽  
Multi Wall Carbon Nanotubes

Transient Free Convective Flow of CNT Water Nanofluid with Heat Transfer from a Moving Cylinder

2020 ◽  
Vol 10 ◽  
Author(s):  
C. Sridevi ◽  
A. Sailakumari
Keyword(s):  
Carbon Nanotubes ◽  
Heat Generation ◽  
Convective Flow ◽  
Volume Fraction ◽  
Vertical Cylinder ◽  
Single Wall Carbon Nanotubes ◽  
Free Convective Flow ◽  
Multi Wall Carbon Nanotubes ◽  
Moving Cylinder ◽  
Variable Surface

Background: In this paper, transient two-dimensional laminar boundary layer viscous incompressible free convective flow of water based nanofluid with carbon nanotubes (CNTs) past a moving vertical cylinder with variable surface temperature is studied numerically in the presence of thermal radiation and heat generation. Methods: The prevailing partial differential equations which model the flow with initial and boundary conditions are solved by implicit finite difference method of Crank Nicolson type which is unconditionally stable and convergent. Results: Influence of Grashof number (Gr), nanoparticle volume fraction ( ), heat generation parameter (Q), temperature exponent (m), radiation parameter (N) and time (t) on velocity and temperature profiles are sketched graphically and elaborated comprehensively. Conclusion: Analysis of Nusselt number and Skin friction coefficient are also discussed numerically for both single wall carbon nanotubes (SWCNTs) and multi wall carbon nanotubes (MWCNTs).

Functionalization of Individual Multi-Wall Carbon Nanotubes during Irradiation and Annealing

2020 ◽  
Vol 62 (11) ◽  
pp. 2173-2183
Author(s):  
V. V. Bolotov ◽  
E. V. Knyazev ◽  
P. M. Korusenko ◽  
S. N. Nesov ◽  
V. A. Sachkov
Keyword(s):  
Carbon Nanotubes ◽  
Multi Wall Carbon Nanotubes

Direct anchoring of Eu3+ complex to derivative surfaces of multi-wall carbon nanotubes (Eu@DSCNTs) for linear fluorescence nanomaterials

2021 ◽  
Vol 853 ◽  
pp. 156880
Author(s):  
Xiaohua Qi ◽  
Wenna Zhang ◽  
Na Yang ◽  
Di Yang ◽  
Igor Bychko ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multi Wall Carbon Nanotubes

scholarly journals Unsteady hybrid-nanofluid flow comprising ferrousoxide and CNTs through porous horizontal channel with dilating/squeezing walls

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Bilal ◽  
Hamna Arshad ◽  
Muhammad Ramzan ◽  
Zahir Shah ◽  
Poom Kumam
Keyword(s):  
Carbon Nanotubes ◽  
Differential Equations ◽  
Numerical Approach ◽  
Hybrid Nanofluid ◽  
Multi Wall Carbon Nanotubes ◽  
Porous Walls ◽  
Industrial Cleaning ◽  
Energy Equations ◽  
Single Wall Nanotubes ◽  
Order Four

AbstractThe key objective of the present research is to examine the hybrid magnetohydrodynamics (MHD) nanofluid (Carbon-nanotubes and ferrous oxide–water) CNT–Fe3O4/H2 flow into a horizontal parallel channel with thermal radiation through squeezing and dilating porous walls. The parting motion is triggered by the porous walls of the channel. The fluid flow is time-dependent and laminar. The channel is asymmetric and the upper and lower walls are distinct in temperature and are porous. With the combination of nanoparticles of Fe3O4 and single and multi-wall carbon nanotubes, the hybrid nanofluid principle is exploited. By using the similarity transformation, the set of partial differential equations (PDEs) of this mathematical model, governed by momentum and energy equations, is reduced to corresponding ordinary differential equations (ODEs). A very simple numerical approach called the Runge–Kutta system of order four along with the shooting technique is used to achieve the solutions for regulating ODEs. MATLAB computing software is used to create temperature and velocity profile graphs for various emerging parameters. At the end of the manuscript, the main conclusions are summarized. Through different graphs, it is observed that hybrid-nanofluid has more prominent thermal enhancement than simple nanofluid. Further, the single-wall nanotubes have dominated impact on temperature than the multi-wall carbon nanotubes. From the calculations, it is also noted that Fe2O3–MWCNT–water has an average of 4.84% more rate of heat transfer than the Fe2O3–SWCNT–water. On the other hand, 8.27% more heat flow observed in Fe2O3–SWCNT–water than the simple nanofluid. Such study is very important in coolant circulation, inter-body fluid transportation, aerospace engineering, and industrial cleaning procedures, etc.

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