Defect Healing of Carbon Nanotubes by Rapid Vacuum Arc Annealing

2007 ◽  
Vol 1057 ◽  
Author(s):  
Jeff Tsung-Hui Tsai ◽  
Jason Li ◽  
Andy Tseng

ABSTRACTA rapid thermal annealing process is demonstrated for healing the defects in carbon nanotubes using a DC vacuum arc discharge system. Multi-walled carbon nanotubes (MWCNTs) grown by chemical vapor deposition at a relatively low temperature (∼650 °C) showed structural imperfections inside the tubes which are known as "bamboo-like" defects. These defects can be thermally annealed to reconstruct the graphitic structure. A vacuum arc discharge system was used to generate high temperatures (∼1800 °C) followed by rapid cooling. The MWCNTs can be rapidly annealed in such a system by several heating and cooling cycles. The annealed samples were characterized by Raman spectroscopy and transmission electron microscopy. The defects were found to be healed when the environment contained water vapor, indicating that oxygen may play an important role in breaking the imperfect graphitic structure and removing the weakly bonded defects during the rapid heating cycles. After breaking the “bamboo” segment, the graphene shell was then reconstructed during the cooling process to produce multi-shell perfection. This method produces effective defect healing and bamboo structure removal from MWCNTs.

2021 ◽  
Vol 6 ◽  
pp. 1
Author(s):  
Putri Ayu Anggoro ◽  
Teguh Endah Saraswati

<p><em>Carbon Nanotube</em> (CNT) memiliki aplikasi potensial yang luas karena sifat kimia dan fisiknya yang sangat baik. CNT disintesis menggunakan prekursor cair dari bahan alam yang. Prekursor cair dari bahan alam dimungkinkan dapat mengganti prekursor berbasis minyak bumi. Minyak kamper, jarak, kayu putih, dan kelapa sawit digunakan sebagai reservoir karbon untuk menghasilkan CNT berdinding banyak (MWCNT). Berbagai metode telah digunakan untuk menghasilkan CNT, termasuk ablasi laser, <em>arc discharge</em> dan proses deposisi uap kimia (CVD). Ulasan ini menjelaskan pembuatan CNT menggunakan metode CVD dikarenakan metode ini adalah metode yang umum digunakan dan sederhana. MWCNT yang dihasilkan dimodifikasi untuk membentuk komposit dengan resin epoksi.</p><p><strong><em>Synthesis of Carbon Nanotubes (CNT) Using Natural Material Precursors and Modified CNTs as CNT/Epoxy Resin Composite: Review. </em></strong>Carbon Nanotubes (CNT) have wide potential applications due to their excellent chemical and physical properties. CNTs were synthesized using liquid precursors from natural materials possibly replacing petroleum-based precursors. Camphor, jatropha, eucalyptus oil, and palm oil are used as carbon reservoirs to produce multi-walled carbon nanotubes (MWCNT). A variety of methods have been used to produce CNTs, including laser ablation, arc discharge, and chemical vapor deposition (CVD) processes. This mini-review explained the manufacture of CNTs using the CVD method as a commonly used and simple method. The synthesized CNT is then modified to be applied to form a composite with epoxy resin</p>


2003 ◽  
Vol 778 ◽  
Author(s):  
Lata Muthuswami ◽  
P. M. Ajayan ◽  
R. E. Geer

AbstractNanomechanical mapping of individual multi-walled carbon nanotubes (MWNTs) has been undertaken to investigate intra-tube variations of mechanical response. Ultrasonic force microscopy has been used to measure the relative axial and radial variations of contact stiffness of individual MWNTs synthesized using chemical vapor deposition (CVD) and arc-discharge (AD) techniques. For CVD-based MWNTs the contact stiffness of the tube was seen to vary strongly across volume defects (axial variation of the tube radius) and is assumed to result from the high crystalline defect density associated with such radial variations. These observations support recent experimental data of effective Young's modulus inferred from electrostatically-induced nanotube vibration amplitudes.


2021 ◽  
Author(s):  
Syed Awais Rouf ◽  
Zahid Usman ◽  
Hafiz Tariq Masood ◽  
Abdul Mannan Majeed ◽  
Mudassira Sarwar ◽  
...  

In this chapter, we will evaluate the synthesis and purification of carbon nanotubes. Carbon nanotubes are cylindrical molecules that consists of graphene (rolled up of a single-layer carbon atom). A wide variety of synthesis techniques such as arc discharge synthesis, laser ablation of graphite/laser vaporization synthesis method, chemical vapor deposition (CVD), high pressure carbon monoxide synthesis and flame synthesis techniques, have been implemented to grow single and multi-walled carbon nanotubes for technological applications. All of the above methods exploit transition metals, like iron, cobalt, and nickel, as a catalyst. There are number of methods (filtering, chromatography and centrifugation) used to purify the carbon nanotubes, but the degree of purity remained questionable in these methods. In order to enhance the purification extent, alternate techniques such as Gas phase purification, Liquid phase purification and Purification by Intercalation are introduced. Here we will discuss the advantages and disadvantages of these purification routes. It will help researchers in selecting appropriate and effective method for synthesis and purification of carbon nanotubes.


Author(s):  
L. Wan ◽  
R. F. Egerton

INTRODUCTION Recently, a new compound carbon nitride (CNx) has captured the attention of materials scientists, resulting from the prediction of a metastable crystal structure β-C3N4. Calculations showed that the mechanical properties of β-C3N4 are close to those of diamond. Various methods, including high pressure synthesis, ion beam deposition, chemical vapor deposition, plasma enhanced evaporation, and reactive sputtering, have been used in an attempt to make this compound. In this paper, we present the results of electron energy loss spectroscopy (EELS) analysis of composition and bonding structure of CNX films deposited by two different methods.SPECIMEN PREPARATION Specimens were prepared by arc-discharge evaporation and reactive sputtering. The apparatus for evaporation is similar to the traditional setup of vacuum arc-discharge evaporation, but working in a 0.05 torr ambient of nitrogen or ammonia. A bias was applied between the carbon source and the substrate in order to generate more ions and electrons and change their energy. During deposition, this bias causes a secondary discharge between the source and the substrate.


2017 ◽  
Vol 104 ◽  
pp. 258-265 ◽  
Author(s):  
Guo-Wei Cheng ◽  
Kevin Chu ◽  
Jeng Shiung Chen ◽  
Jeff T.H. Tsai

2010 ◽  
Vol 431-432 ◽  
pp. 466-469
Author(s):  
Dong Can Zhang ◽  
Bin Shen ◽  
Fang Hong Sun ◽  
Ming Chen ◽  
Zhi Ming Zhang

The diamond and diamond-like carbon (DLC) films were deposited on the cobalt cemented tungsten carbide (WC-Co) cutting tools respectively adopting the hot filament chemical vapor deposition (HFCVD) technique and the vacuum arc discharge with a graphite cathode. The scanning electron microscope (SEM), X-ray diffraction spectroscopy (XRD) and Raman spectroscopy were used to characterize the as-deposited diamond and DLC films. To evaluate their cutting performance, comparative turning tests were conducted using the uncoated WC-Co and as-fabricated CVD diamond and DLC coated inserts, with glass fiber reinforced plastics (GFRP) composite materials as the workpiece. The research results exhibited that diamond and DLC coated inserts had great advantages in cutting tests compared to uncoated insert. The flank wear of the CVD diamond coated insert maintained a very low value about 50μm before the cutting tool failure occurred. For the DLC coated insert, its flank wear always maintained a nearly constant value of 70~200μm during whole 45 minutes turning process. The flank wear of CVD diamond coated insert was lower than that of DLC coated insert before diamond films peeling off.


2008 ◽  
Vol 14 (S2) ◽  
pp. 304-305
Author(s):  
M Ellis ◽  
T Jutarosaga ◽  
S Smith ◽  
Y Wei ◽  
S Seraphin

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008


2013 ◽  
Vol 667 ◽  
pp. 534-537
Author(s):  
M.Z. Nuraini ◽  
S. Aishah ◽  
S.F. Nik ◽  
Mohamad Rusop

Fermented tapioca which is a new starting material was used as a carbon precursor. Carbon nanotubes (CNTs) were deposited on silicon wafer (Si) by Thermal Chemical Vapor Deposition (TCVD). The gas flow of Argon (Ar) was constant at 70 bubbles per minute and 20 minutes of deposition time. Before the deposition process, silicon was coated with Nickel using spin coater. Various parameters such as amount of inoculums have been studied. Chemical functional groups of carbon nanotubes were characterized using FT-IR Spectroscopy. The FT-IR result shows peaks attributed to multi–walled carbon nanotubes (MWCNT) vibration modes.


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