Yunasfi .
Pusat Teknologi Bahan Industri Nuklir (PTBIN) – BATAN Kawasan Puspiptek, Serpong, Tangerang

Published : 10 Documents
Articles

Found 10 Documents
Search

PEMANFAATAN TEKNIK HEM UNTUK PENUMBUHAN CNT DARI GRAFIT MENGGUNAKAN Ni SEBAGAI KATALIS = UTILIZATION OF HEM TECHNIQUE FOR GROWTH OF CNT FROM GRAPHITE POWDERS BY USING Ni AS CATALYST ., Yunasfi; Purwanto, P.; ., Mashadi
Majalah Ilmiah Pengkajian Industri Vol 10, No 1 (2016): Majalah Ilmiah Pengkajian Industri
Publisher : BPPT

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29122/mipi.v10i1.101

Abstract

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.  
SIFAT MAGNETORESISTANCE BAHAN KOMPOSIT Fe0,2C0,8 SEBELUM DAN SESUDAH IRADIASI SINAR GAMMA PADA DOSIS 250 kGy ., Yunasfi; Purwanto, Setyo; A, Wisnu A
Jurnal Sains dan Teknologi Nuklir Indonesia Vol 10, No 1 (2009): Februari 2009
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (129.617 KB)

Abstract

Telah dilakukan penelitianterhadap sifat magnetoresistance bahan komposit Fe0,2C0,8 sebelum dan sesudah iradiasidengan sinar gamma pada dosis 250 kGy. Bahan komposit Fe0,2C0,8 dibuat dari campuranserbuk Fe dan serbuk C, dengan rasio komposisi 20% berat Fe dan 80% berat C. Padapenelitian ini, diamati perubahan sifat magnetoresistance bahan komposit Fe0,2C0,8 setelahdiiradiasi dengan sinar gamma pada dosis 250 kGy. Pengujian struktur Fe0,2C0,8 dilakukandengan difraktometer sinar-X (XRD) dan karakterisasi sifat magnetoresistance dilakukandengan metode Four Point Probe. Hasil pengujian dengan XRD menunjukkan penurunanintensitas puncak difraksi dari fasa Fe dan C oleh radiasi sinar gamma, sedangkan hasilpengukuran magnetoresistance menunjukkan peningkatan nilai magnetoresistance bahantersebut. Peningkatan nilai ini mencapai 5 kali pada medan magnet 7,5 kOe setelah diiradiasidengan sinar gamma. Hal ini disebabkan oleh adanya cacat struktur yang terbentuk dalambahan komposit Fe0,2C0,8 akibat interaksi sinar gamma dengan bahan komposit tersebut yangmenimbulkan perubahan intensitas interaksi magnetik di dalam bahan ini.
GROWTH OF CARBON NANOTUBES WITH MILLING TECHNIQUE USING Fe AS A CATALYST. ., Yunasfi; Mustofa, Salim; ., Muflikhah
Jurnal Sains Materi Indonesia Vol 14, No 1 (2012): Oktober 2012
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (41.834 KB)

Abstract

Growing of carbon nanotubes (CNT) with a milling technique using particles Fe as grower catalyst has been done. Fe-C nano-sized powder mixture are prepared froma mixture of micron-sized graphite and Fe powders in a variety of weight percent Fe (1% to 5% by weight Fe), and then milled for 50 hours using a High Energy Milling (HEM) facility. X-ray diffraction pattern shows the presence of C (002), C (004) and C (110) peaks and Fe peaks of (101) and (200). Carbon peaks decrease in intensity with increasing wt%Fe and tend to becoming amorphous, while Fe peaks sharply increasing. Microstructure observation by TEM showed an initial growth of CNTs with dimensions affected by Fe content. The sample, containing 2%Fe, formed CNT structure better than other samples. CNT formation was also confirmed fromthe Raman spectrum showing the presence of the G-band at 1590 cm-1 and D-band peak at 1310 cm-1 with and D-band intensity, ID higher than IG and absence of RBM-band peak at low wave numbers. This condition is a typical spectrum for a material having a Multi Wall Carbon Nanotube (MWCNT) structure. The highest ratio of ID/IG for 2% Fe sample support the analysis of CNT-dimension from Transmission Electron Microscope (TEM) observation. In general, the data obtained in this study showed that Fe can serve as a catalyst for CNT growth.Keywords: Graphite, CNT, Milling technique, Precursor Fe.
GROWTH OF CARBON NANOTUBE BY APPLYING ION IMPLANTATION TECHNIQUE Mustofa, Salim; ., Yunasfi
Jurnal Sains Materi Indonesia Vol 13, No 2 (2012): Februari 2012
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (41.834 KB)

Abstract

The use of ion implantation technique for growing carbon nanotubes (CNT) has been studied. Implantation technique with its high and focused energy is used for implanting Ni+ ion, which can act as catalyst for CNT growth. CNT was grown by implantation of Ar(sup>+ and Ni+ ion to the nanostructured carbon thin film that were deposited on Si(100) substrate. The dose of ion implantation parameter was varied between 5 x 1015 to 1 x 1017 ion/cm2. After implantation, the phase identification by X-Ray diffraction (XRD) and observations of surface and cross section morphology of samples by Scanning Electron Microscopy (SEM) in order to investigate the growth of CNT were carried out. The XRD analysis shows the peak of C(002), Ni(010) and Si(100) on the C/Si thin film samples after ion implantation, which indicate the carbon filmstill in a crystalline structure. The peak of Ni(010) is slightly decreased with the increasing of ion dose. The observation by SEM shows that the greater the dose of implants, the more unflat surface found on a thin film.While from the observation of cross section, it was indicated that the higher dose implants, more clearly the growth of CNTs on the surface of C/Si thin film. CNT is predicted to grow as a result of interaction between ion radiations with carbon, leading to the formation of CNTs.Keywords: Thin Film, CNT, Ion Implantation Technique, Dose.
SYNTHESIS AND CHARACTERIZATION OF GRAPHITE NANOSTRUCTURE THIN FILM WITH SPUTTERING TECHNIQUE ., Yunasfi; Mustofa, Salim; ., Deswita
Jurnal Sains Materi Indonesia Vol 13, No 1 (2011): Oktober 2011
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (41.834 KB)

Abstract

Synthesis and characterization of graphite nanostructure thin film using the DC-sputtering technique has been carried out. Nanostructured graphite for target of deposition using DC-Sputtering technique has been prepared by milling technique using High Energy Milling (HEM) with the variation of milling time between 50 hours until 100 hours. First, the graphite target was prepared by doing a compaction using press machine to the nanostructured graphite powder got from milling process. Secondly, a thin film of graphite was fabricated using DC-Sputtering technique. The phase identification of nanostructured graphite thin film were carried out using X-Ray Diffraction (XRD), and the surface and cross section morphology of thin film were observed using Scanning Electron Microscopy (SEM). XRD identification shows the presence of peaks of Si(100) and C(002) in all conditions of preparing powder using for target, but a shift of the angel‘s peak to the left and the decreasing of peak intensity were found. While the observation using SEM to surface morphology of thin film shows that the form of thin films are mostly homogeneous, smooth and flat at the milling time of 50-75 hours. From the SEM photograph of cross section, it is shown that there is a tendency of the more commonly found particles of droplets on the surface of thin film with the increasing of milling process against the carbon powder as a constituent of pellets for the DC-Sputtering targets, especially in the case of C/Si thin film fabricated using target prepared by milling for 100 hours, the morphology of surface was worst.Keywords: Graphite Thin Film, Nanostructure, DC-Sputtering Technique, HEM, Carbon Target.
EFFECT OF INCREASING Ar+ ION DOSAGE ON THE GROWTH PROCESS OF CARBON NANOTUBES FROM NANOCOMPOSITE Fe-C ., Yunasfi
Jurnal Sains Materi Indonesia Vol 12, No 3 (2011): Juni 2011
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (41.834 KB)

Abstract

A study on the effect of Ar+ ion dose in the growth process of Carbon Nanotubes (CNT) of nanocomposite Fe-C with ion implantation technique has been carried out. Compaction of Fe-C as a target in producing nanocomposite Fe-C thin film was composed of nanocomposite Fe-C powder, which is prepared through milling process by High Energy Milling (HEM) technique for 50 hours. The morphology of milled Fe-C powder was observed by SEM to determine the particle size. Furthermore, the milled Fe-C powder was compacted to be used as target for DC-Sputtering technique. Formed Fe-C thin film then was implanted by Ar+ ion with argon gas as an ion source at the doses between 5 x 1015 to 1 x 1017 ions/cm2. Next, the phase of Fe-C thin film was identified by XRD, and the cross section was observed by SEM. The result of XRD after implantation showed the reduction of diffraction peak intensity with the increasing of Ar + ion dose. The result of SEM showed that particle of Fe-C powder was in nano order size. From SEM also showed the uneven surface, this unevenness became clearly with the increasing of dose, and the formation of CNTs on the surface of thin film was also exhibited.Keywords: Nanocomposite Fe-C, Ion Implantation, CNT, Fe-C Thin Film, Dose.
Effect of Mechanical Treatment on The Electrical Properties of Graphite Materials ., Yunasfi; Mustofa, Salim
Jurnal Sains Materi Indonesia Vol 11, No 3 (2010): Juni 2010
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (41.834 KB)

Abstract

Measurement of electrical properties of graphite materials as the mechanical treatment result with high energy milling (HEM) techniques was carried out. The carbon powder was milled using HEM by varying the milling time from 25 hours to 100 hours, and afterwards the graphite material was formed to a pellet under compaction up to 20 ton/cm2. The measurements result of electrical properties using LCR (Inductance, Capacitance, Resistance) meter showed that milling process to graphite causes the increasing of conductivity and capacitance values and these values were increasing with the increase of milling times. Before milling, the conductivity value is 3.5976 Siemens/cm and the value of capacitance is 0.2223 μF at 100 kHz frequence. Increasing of conductivity value reached 26% and capacitance value reached 66% after milling for 100 hours. These incresing are analized due to decreasing of graphite powder particle size causing by longer milling time and result in higher electrical conductivity.Keywords: Mechanical Treatment Graphite, Electrical Properties, Conductivity, High Energy Milling. 
EFEK IMPLANTASI ION Ni+ DAN Ar+ TERHADAP SIFAT MAGNETIK LAPISAN TIPIS C/Si ., Yunasfi
Jurnal Sains dan Teknologi Nuklir Indonesia Vol 15, No 1 (2014): Februari 2014
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (208.786 KB)

Abstract

EFEK IMPLANTASI ION Ni+ DAN Ar+ TERHADAP SIFAT MAGNETIK LAPISAN TIPISC/Si. Telah dilakukan studi efek implan ion Ni+ dan ion Ar+ terhadap sifat magnetik lapisan tipisC/Si (100). Implantasi ion Ni+ dan ion Ar+ terhadap lapisan tipis C/Si dilakukan dengan dosissampai 5 x 1016 ion/cm2. Hasil identifikasi XRD menunjukkan adanya puncak intensitas difraksiC (002) dan Ni (100). Implantasi ion dapat menyebabkan penurunan puncak intensitas difraksiC (002). Puncak intensitas difraksi C (002) semakin menurun seiring dengan bertambahnyadosis ion, sedangkan puncak intensitas difraksi Ni (100) semakin tinggi seiring dengan bertambahnyadosis ion. Hasil ini menunjukkan telah terjadi distribusi atom Ni pada permukaanlapisan tipis C/Si. Hasil pengamatan morfologi permukaan menggunakan SEM/EDS,menunjukkan adanya atom Ni yang tersebar pada permukaan lapisan tipis C/Si. Hasilpengukuran sifat magnetik dengan metode VSM (Vibrating Sample Magnetometer)menunjukkan adanya perubahan sifat magnetik pada lapisan tipis C/Si dengan penambahandosis implan. Sifat magnetik ini meningkat seiring dengan penambahan dosis ion Ni+, yangditunjukkan dengan peningkatan nilai-nilai Ms (saturated magnetization), Mr (remanentmagnetization) dan Hc (coercive field), masing-masing sebesar 28%, 21% dan 42%. Hasilpengukuran sifat GMR dengan Four Point Probe juga menunjukkan peningkatan nilai nisbahMR sekitar 26% pada medan magnet 7,5 kOe seiring dengan peningkatan dosis ion.Kata kunci : lapisan tipis C/Si, implantasi ion, sifat magnetik
KARAKTERISASI SIFAT LISTRIK DAN MORFOLOGI PERMUKAAN BAHAN KOMPOSIT MWCNT-Fe Purwanto, P; ., Yunasfi; Purnama, S; ., Mashadi
Urania Jurnal Ilmiah Daur Bahan Bakar Nuklir Vol 21, No 1 (2015): Februari 2015
Publisher : Urania Jurnal Ilmiah Daur Bahan Bakar Nuklir

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

KARAKTERISASI SIFAT LISTRIK DAN MORFOLOGI PERMUKAAN BAHAN KOMPOSIT MWCNT-Fe. Telah dilakukan pembuatan komposit MWCNT(Multi Walled Carbon Nanotube)-Fe dengan metode reaksi padatan. Bahan MWCNT-Fe dipelet dengan tekanan 5 ton dengan diameter sampel 1 cm, selanjutnya pemanasan bahan komposit dari temperatur 30°C sampai 250°C. Analisis fasa atau struktur kristal MWCNT-Fe dilakukan dengan difraksi sinar-X. Hasil idenfikasi dan analisis XRD menunjukkan bahwa pola difraksi yang nampak adalah puncak-puncak karbon (CNT) dan besi (Fe). Ukuran kristalit komposit MWCNT-Fe berkisar antara 8,07 sampai 28,28 nm. Hasil analisis morfologi permukaan dengan SEM menunjukkan bahwa komposit MWCNT-Fe telah terbentuk. Dari analisis terhadap komposit MWCNT-Fe ditemukan adanya unsur karbon (CNT) dan besi pada permukaan dan pengotor yang lain, komposit MWCNT-Fe memiliki morfologi permukaan tidak jelas terlihat pada komposit CNT-1 sampai CNT-5. Pengukuran sifat listrik pada komposit MWCNT-Fe yang dilakukan meliputi perubahan konduktivitas terhadap perubahan frekuensi dan sebagai fungsi temperatur. Hasil pengukuran menunjukkan konduktivitas komposit CNT-1 dan CNT-3 naik seiring dengan naiknya temperatur pemanasan, sedangkan CNT-5 turun.CHARACTERIZATION OF ELECTRICAL PROPERTIES AND SURFACE MORPHOLOGY OF THE MWCNT-Fe COMPOSITE MATERIALS. MWCNT (Multi Walled Carbon Nanotube)-Fe had been fabricated by solid state reaction method. MWCNT - Fe was compacted in dies diameter at 1 cm with pressure at 5 tons, then samples were heated from 30 °C to 250 °C. The phase analysis of MWCNT - Fe were done by X-ray diffraction. The result idenfication and analysis from XRD pattern showed carbon peak (CNT) and iron (Fe). The crystallite size of MWCNT-Fe ranged from 8.07 to 28.28 nm. The results of surface analysis by SEM showed that the composites MWCNT - Fe were formed. Analysis on MWCNT-Fe composites reveal that the elemental carbon (CNT), iron and other impurities were found on the surface of composites, MWCNT-Fe composites had granular morphology that not visible at the composites CNT-1 to CNT-5. The electrical properties measurement of the composites MWCNT-Fe was performed on electical conductivity againts frequency changes and as a function of temperature. The measurement results show that the electrical conductivity of CNT-1 and CNT-3 increased during increasing the temperature, contrary to the CNT-5.
PENGARUH WAKTU MILLING SERBUK GRAFIT TERHADAP KANDUNGAN UNSUR PENGOTOR YANG DIANALISIS DENGAN TEKNIK ANALISIS AKTIVASI NEUTRON (AAN) ., Yunasfi; M., Th. Rina
Urania Jurnal Ilmiah Daur Bahan Bakar Nuklir Vol 15, No 2 (2009): April 2009
Publisher : Urania Jurnal Ilmiah Daur Bahan Bakar Nuklir

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (473.42 KB)

Abstract

ABSTRAK PENGARUH WAKTU MILLING SERBUK GRAFIT TERHADAP UNSUR PENGOTOR YANG DIANALISIS DENGAN TEKNIK ANALISIS AKTIVASI NEUTRON (AAN). Telah dilakukan penelitian tentang efek waktu milling serbuk grafit terhadap kuantitas unsur pengotor yang dianalisis dengan teknik analisis aktivasi neutron. Proses milling serbuk grafit dilakukan dengan teknik High Energy milling (HEM) pada temperatur ruang, menggunakan vial dan bola-bola yang terbuat dari bahan Stainless Stell (SS). Milling dilakukan masing-masing selama 25, 50, 75 dan 100 jam. Hasil analisis  kualitatif dengan teknik AAN menunjukkan bahwa unsur-unsur pengotor yang terkandung di dalam serbuk grafit adalah Fe, Cr, V, Co, Sc, Mn, Al, Eu, La, Na, Se, Hf, dan Th. Dengan adanya proses milling terhadap serbuk grafit maka konsentrasi unsur-unsur pengotor V, Mn, Cr, dan Fe meningkat. Peningkatan terbesar kuantitas unsur-unsur pengotor untuk Vanadium (V) pada waktu milling 50 jam (554,41 %), Mn pada waktu milling 25 jam (190,13%), Cr pada waktu milling 50 jam (837,07%) dan Fe pada waktu milling 50 jam (53,31%).  Pada proses milling 100 jam diperoleh kandungan unsur-unsur pengotor paling rendah. Dengan demikian, waktu milling yang optimal untuk pemrosesan serbuk grafit adalah 100 jam.   Kata Kunci : Unsur pengotor, serbuk grafit, Analisis Aktivasi Neutron, High Energy Milling.   ABSTRACT EFFECTS OF MILLING TIMES OF GRAPHITE POWDERS AGAINST THE IMPURITIES ANALYZED BY NEUTRON ACTIVATION ANALYSIS. Research about the effects of milling times of graphite powders against the impurities analyzed by with Neutron Activation Analysis (NAA) technique was carried out. Milling process of graphite powders was carried out using High Energy Milling (HEM) technique at room temperature using vial and balls mill made from Stainless Steel (SS) material. Graphite powder was milled in various times from 25 hours until 100 hours. Qualitative analysis by AAN showed that the impurities detected in graphite powders were Fe, Cr, V, Co, Sc, Mn, Al, Eu, La, Na, Se, Hf, and Th elements. The results showed that milling process of graphite powders increased the concentration of V, Mn, Cr, and Fe. The largest increasing of impurities are Vanadium (V) for 50 hours (554,41%), Mn for 25 hours (190,13 %), Cr for 50 hours (837,07%) and Fe for 50 hours (53,31 %) milling times. Milling process for 100 hours has the lowest concentrations of impurites, therefore, the optimum for processing of graphite powders was 100 hours. Keywords: Impurities, graphite powders, Neutron Activation Analysis, High Energy Milling