scholarly journals Effect of milling time on the formation of carbon nanotube by mechano-thermal method

2015 ◽  
Vol 38 (4) ◽  
pp. 857-863 ◽  
Author(s):  
ERTAN EVİN ◽  
ÖMER GÜLER ◽  
MUSTAFA AKSOY ◽  
SEVAL HALE GÜLER
2016 ◽  
Vol 10 (1) ◽  
pp. 35-40
Author(s):  
Yunasfi . ◽  
P. Purwanto ◽  
Mashadi .

Utilization of HEM (high energy milling) technique for growth of CNT (carbon nanotube) from graphite powders by using Ni as catalyst was carried out. Milling process performed on a mixture of graphite powder and nickel powder (Ni-C powders) with the ratio of weight percent of 98%: 2%, with a variation of milling time between 25 up to 75 hours. Characterization using PSA (Powder Size Analyzer), SAA (Surface Area Analyzer), TEM (Transmission Electron Microscope) and Raman Spectroscopy performed to obtain information about particle size, surface area, morphology and the structure bonding of the milled powder respectively. The analysis results of Ni-C powders using PSA and SAA showed the smallest particle size and biggest surface area obtained after milling process for 50 hours, i.e. 80 nm and 705 m2/g, respectively. TEM observations revealed formation of flat fibers which quantity increased with increasing milling time. This flattened fiber behave as an initiator for the growth of CNTs. Ni-C powder milling for 50 hours results more clearly show the growth of CNTs. Analysis by Raman Spectroscopy showed two bands at 1582 cm−1 as a peak of G band and at 1350 cm-1 as a peak of D band. These spectra are typical for sp2 structure. The position of G band peak is close to 1600 cm-1 as the evidence of a change to nano-crystalline graphite. The highest intensity of D band shown in the milling process for 50 hours, which indicates that this milling time produces more graphite-like structure compared to other conditions, and is predicted good for growing CNTs. AbstrakPemanfaatan teknik HEM (High Energy Milling) untuk penumbuhan CNT (carbon nanotube) dari serbuk grafit dengan menggunakan Ni sebagai katalis. Proses milling dilakukan terhadap campuran serbuk grafit dan serbuk nikel (serbuk Ni-C) dengan perbandingan berat 98% : 2%, dengan variasi waktu milling antara 25-75 jam. Karakterisasi menggunakan fasilitas PSA (Particle Size Analyzer), SAA (Surface Area Analyzer), dan TEM (Transmission Electron Microscope) serta Raman Spektroscopy yang masing-masingnya untuk mendapatkan informasi tentang ukuran partikel, luas permukaan dan morfologi serta struktur ikatan serbuk hasil milling. Hasil analisis serbuk Ni-C dengan PSA dan SAA menunjukkan ukuran partikel paling kecil dan luas permukaan paling besar diperoleh setelah proses milling selama 50 jam, masing-masing 80 nm dan 705 m2/g. Pengamatan TEM menunjukkan serbuk-serbuk berbentuk serat pipih dengan kuantitas yang meningkat dengan bertambahnya waktu milling. Serat pipih ini perupakan cikal bakal penumbuhan CNT. Serbuk Ni-C hasil milling menunjukkan penumbuhan CNT terlihat lebih jelas setelah milling selama 50 jam. Hasil analisis dengan Raman Spectroscopy memperlihatkan puncak G band pada bilangan gelombang 1582 cm−1 yang merupakan spektrum untuk struktur sp2 dari grafit dan puncak D band pada bilangan gelombang 1350 cm-1 yang mungkin merupakan deformasi struktur grafit. Posisi puncak G band mendekati 1600 cm-1 menjadi bukti perubahan ke grafit nano kristal. Intensitas D band tertinggi ditunjukkan oleh sistem komposit Ni-C hasil proses milling selama 50 jam dan hal ini sebagai indikasi bahwa proses milling selama 50 jam terhadap sistem komposit Ni-C lebih berstruktur mirip grafit (graphitic-like material) dibanding kondisi lainnya dan diprediksi bagus untuk menumbuhkan CNT. Dengan demikian, waktu milling yang optimal untuk penumbuhan CNT dari serbuk grafit dengan menggunakan Ni sebagai katalis adalah adalah 50 jam.  


2021 ◽  
Vol 878 ◽  
pp. 89-97
Author(s):  
Shogo Kimura ◽  
Junki Ueda ◽  
Hideaki Tsukamoto

Carbon nanotube (CNT) has been one of promising candidates as a reinforcement in metal matrix composites (MMCs) for its variety of excellent properties such as lightweight, high strength etc. It is necessary to disperse CNT to the level of each one in order to lead to efficiently reflect the excellent essential physical properties of CNT in the composites. This research investigates fabrication processes linked with dry ball milling and cold pressing followed by sintering to uniformly disperse CNT in aluminum (Al) matrix. It was found that dispersibility of CNT were improved with increasing ball milling time based on observation of morphology of mixed powders and the composites using SEM. Vickers hardness and tensile strength of CNT/ Al composites increased with increasing ball milling time up to 24 hours, while they were constant or decreased because of increase of voids in case of longer than 24 hours of ball milling time.


2017 ◽  
Vol 122 ◽  
pp. 296-306 ◽  
Author(s):  
Amar J Albaaji ◽  
Elinor G Castle ◽  
Mike J Reece ◽  
Jeremy P Hall ◽  
Sam L Evans

2020 ◽  
Vol 54 (23) ◽  
pp. 3457-3469 ◽  
Author(s):  
Francesco Zangrossi ◽  
Fang Xu ◽  
Nick Warrior ◽  
Petros Karapappas ◽  
Xianghui Hou

Several ice protection strategies have been developed to overcome the icing hazards in the aerospace industry. The electro-thermal method is one of the popular approaches to prevent ice accretion and accumulation on aircraft surfaces. Given the increasing requirement of composites on aircraft structures, metal frameworks/fibre-reinforced composites have been developed as a de-icing solution for the new generation aircraft. The present work aimed to fabricate self-heating multi-wall carbon nanotubes based composites for ice protection and to study their electro-thermal and mechanical characteristics. Carbon nanotube buckypapers (CNPs) were prepared and embedded in fibre reinforced polymer composites by two methods: pre-preg and resin impregnation. The influence of the carbon nanotube network structure on the mechanical properties and electrical characteristics of the composites was evaluated. Mechanical tests, three-point flexural test and interlaminar shear strength test demonstrated improved mechanical characteristics of the CNP based composites. De-icing performance of the composites was conducted through a heating test in a climate chamber at −20℃. The results indicated that the CNP-based composite is a promising self-heating material candidate for ice protection systems.


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3823 ◽  
Author(s):  
Ha ◽  
Lee ◽  
Park

For practical use of carbon nanotube (CNT) composites, especially in electronic applications, uniform dispersion of a high concentration of CNTs in a polymer matrix is a critical challenge. Three-roll milling is one of most reliable dispersion techniques. We investigate the effect of three-roll milling time on CNT length and the electrical properties of a CNT/polydimethylsiloxane composite film with 10 wt% CNTs. During the milling process, the CNT length is decreased from 10 to 1–4 μm by mechanical shear forces. The electrical conductivity increases after 1.5 min of milling owing to dispersion of the CNTs but decreases with increasing milling time owing to the decrease in the CNT length. Considering the changes in the electrical conductivity of the CNT composite and CNT length, we determined how to optimize the three-roll milling time to obtain a suitable dispersion state.


Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).


Author(s):  
J.P. Benedict ◽  
Ron Anderson ◽  
S. J. Klepeis

Traditional specimen preparation procedures for non-biological samples, especially cross section preparation procedures, involves subjecting the specimen to ion milling for times ranging from minutes to tens of hours. Long ion milling time produces surface alteration, atomic number and rough-surface topography artifacts, and high temperatures. The introduction of new tools and methods in this laboratory improved our ability to mechanically thin specimens to a point where ion milling time was reduced to one to ten minutes. Very short ion milling times meant that ion milling was more of a cleaning operation than a thinning operation. The preferential thinning and the surface topography that still existed in briefly ion milled samples made the study of interfaces between materials such as platinum silicide and silicon difficult. These two problems can be eliminated by completely eliminating the ion milling step and mechanically polishing the sample to TEM transparency with the procedure outlined in this communication. Previous successful efforts leading to mechanically thinned specimens have shown that problems center on tool tilt control, removal of polishing damage, and specimen cleanliness.


Author(s):  
H.-S. Philip Wong ◽  
Deji Akinwande

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