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All Journal Jurnal Silvikultur Tropika (JST) Tunas Geografi SEMIRATA 2015 Acta Aquatica: Aquatic Sciences Journal OLDI (Oseanologi dan Limnologi di Indonesia) JURNAL PENDIDIKAN TAMBUSAI Majalah Ilmiah Pengkajian Industri Metalurgi Jurnal Material dan Energi Indonesia

yunasfi yunasfi

Pusat Sains dan Teknologi Bahan Maju-BATAN, Kawasan Puspiptek Serpong, Tangerang

Author-ID : 425436

Aerospace Engineering Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Earth & Planetary Sciences Education Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology Social Sciences Transportation Other

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Pengaruh Waktu Milling Terhadap Mikrostruktur dan Sifat Magnetik Komposit NiFe2O4-NdFeO3 [Influence Of Milling Time on Microstructure and Magnetic Properties of NiFe2O4-NdFeO3 Composite] Mulyawan, Ade; Yunasfi, Yunasfi; Adi, Wisnu Ari
Metalurgi Vol 32, No 3 (2017): Metalurgi Vol. 32 No. 3 Desember 2017
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

The development of electromagnetic wave and microwave absorbing materials was important to overcome the electromagnetic wave interference in communication technology and in the development of radar materials for military purposes. In this study the composite which contained two different phases of NiFe2O4-NdFeO3 has successfully synthesized using Fe2O3, NiO, and Nd2O3 as starting materials through solid state reaction method. The composites were made by varying milling times from 10, 15, 20, and 25 hours then followed by sintering process at 1200 °C for 3 hours. Phase identification was performed using XRD (x-ray diffractometer) which revealed only NiFe2O4 and NdFeO3 phases. The crystallite size of the NiFe2O4 phase is in the range of 59-68 nm, and NdFeO3in the range of 62-65 nm. The agglomeration of particles was observed by using SEM (scanning electron microscope). Referring to the characterization result of the magnetic properties by using VSM (vibrating sample magnetometer), it is known that the parameters of the magnetic properties such as magnetization saturation (Ms), magnetization remanence (Mr), and coercivity (Hc) are highly dependent on the mass fraction, crystallite size,and the homogenity of the phase composition.AbstrakPengembangan bahan penyerap gelombang elektromagnetik dan gelombang mikro sangat penting dilakukan untuk mengatasi masalah interferensi gelombang elektromagnetik pada teknologi komunikasi serta pada material radar untuk tujuan militer. Pada penelitian ini berhasil dilakukan pembuatan material penyerap gelombang elektromagnetik komposit fasa NiFe2O4-NdFeO3 dengan menggunakan Fe2O3, NiO, dan Nd2O3 melalui reaksi padatan. Sampel komposit dimilling dengan variasi waktu 10, 15, 20, dan 25 jam dan selanjutnya disinter pada suhu 1200 oC selama 3 jam. Identifikasi fasa dilakukan dengan X-ray Diffractometer (XRD) menunjukan bahwa komposit hanya terdiri dari fasa NiFe2O4 dan NdFeO3. Ukuran kristalit fasa NiFe2O4 berada pada kisaran 59-68 nm, sedangkan fasa NdFeO3 pada kisaran 62-65 nm. Pengamatan morfologi permukaan dilakukan menggunakan Scanning Electron Microscope (SEM). Berdasarkan nilai parameter sifat magnetik yang dihasilkan menggunakan Vibrating Sample Magnetometer (VSM) seperti magnetisasi saturasi(Ms), magnetisasi remanen (Mr), dan koesivitas (Hc) sangat bergantung pada fraksi massa, ukuran kristalit, dan homogenitas fasa yang terbentuk.

KARAKTERISASI NANOSTRUKTUR KARBON DARI GRAFIT HASIL MILLING[Characterization of Nanostructured Carbon from Graphite as Milling Product] Yunasfi, Yunasfi
Metalurgi Vol 27, No 3 (2012): Metalurgi Vol.27 No.3 Desember 2012
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

KARAKTERISASI NANOSTRUKTUR KARBON DARI GRAFIT HASIL MILLING. Telah dilakukankarakterisasi nanostruktur karbon dari grafit hasil milling. Nanostruktur karbon dibuat melalui proses millingdengan teknik high energy milling (HEM) terhadap serbuk grafit dengan variasi waktu milling antara 25 jamsampai 100 jam. Serbuk grafit hasil milling kemudian diidentifikasi fasanya dengan metoda difraktometer sinarx(XRD), ukuran partikel yang terbentuk dengan metoda particle size analyzer (PSA) dan diamati secara detiltopologinya dengan metoda transmission electron microscopy (TEM). Hasil identifikasi fasa terhadap serbukgrafit hasil milling menunjukkan bahwa hanya muncul puncak difraksi C(002) dan C(004). Hal ini menunjukkanbahwa struktur grafit masih didominasi oleh fasa heksagonal. Intensitas puncak difraksi ini semakin rendahseiring dengan bertambahnya waktu milling. Hasil analisa dengan PSA menunjukkan terbentuknya karbonnanostruktur hasil milling, dimana ditunjukkan bahwa ukuran partikel karbon semakin kecil seiring denganpeningkatan waktu milling, yaitu dari 540 nm (25 jam) menjadi 190 nm (75 jam). Hasil analisa TEMmenunjukkan adanya serat-serat pipih panjang berukuran diameter 10 - 75 nm dan panjang 20 - 200 nm.Kuantitas serat karbon ini semakin banyak seiring dengan peningkatan waktu milling. Hal ini menunjukkanbahwa akibat adanya tumbukan antara partikel karbon dengan bola-bola milling selama proses millingmengakibatkan penghancuran partikel-partikel karbon sampai ke ukuran nano serta pembentukan serat karbon. AbstractCharacterization of nanostructured carbon from graphite as milling product of High Energy Milling (HEM)technique was carried out. Nanostructured Carbon was prepared by milling process against the graphitepowder with various of milling time between 25 hours up to 100 hours. A milled graphite powder was thenidentified their phase by using phase identification with X-Ray Diffractometer methods, formed particle sizewas measured by Particle Size Analyzer (PSA) and the detail phase including the tophology andmeasurement of particle size were observed with Transmission Electron Scanning (TEM) methods. Theresult of identification phase of the graphite powder milling results showed that the intensity of diffractionpeaks which appear only diffraction peaks for carbon C(002) C(004) and C(110), while for other atoms donot identified. This indicates that the graphite structure is still dominated by the hexagonal phase. Theintensity of diffraction peaks is lower along with increasing milling time. PSA analysis result shows theformation of carbon nanostructure as the result of milling process, which the carbon particle size decreaseswith the increasing of milling time; from 540 nm (25 hours) to 190 nm (75 hours). TEM analysis resultshows the existence of long small fiber with the size of 10 – 75 nm and the length of 20 – 200 nm. Thisshows that the result of collisions between particles of graphite powder with milling balls during millingprocess, resulting in the destruction of the graphite particles until nano size and also in the forming of carbonfiber.

SIFAT LISTRIK DAN MAGNETIK LAPISAN TIPIS NANOKOMPOSIT Fe-C/Si(100)[Electrical and Magnetic Properties of Fe-C/Si(100) Nanocomposite Thin Film.] Yunasfi, Yunasfi; Mashadi, Mashadi; Yusuf, Saeful
Metalurgi Vol 28, No 2 (2013): Metalurgi Vol.28 No.2 Agustus 2013
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

SIFAT LISTRIK DAN MAGNETIK LAPISAN TIPIS NANOKOMPOSIT Fe-C/Si(100). Telah dilakukan karakterisasi sifat listrik dan magnetik lapisan tipis nanokomposit Fe-C/Si(100). Nanokomposit dan nanostruktur karbon yang mengandung nanopartikel besi menunjukkan sifat listrik dan magnetik, sehingga banyak diaplikasikan di bidang elektromagnetik dalam bentuk lapisan tipis. Tujuan dari penelitian ini adalah mengamati sifat listrik dan magnetik lapisan tipis nanokomposit Fe-C/Si(100) dalam rangka pengaplikasiannya di bidang sensor. Nanokomposit Fe-C dibuat dari campuran serbuk grafit dan Fe dalam berbagai variasi persen berat Fe (1%-3% berat Fe) dengan teknik high energy milling (HEM) selama 50 jam. Setelah serbuk campuran Fe-C dikompaksi dengan mesin pres, bahan ini dipakai sebagai target sputtering untuk menumbuhkan lapisan tipis nanokomposit Fe-C diatas substrat Si(100). Hasil pengamatan dengan SEM menunjukkan bahwa lapisan tipis memiliki permukaan rata dan halus, partikel Fe-C terdeposisikan secara merata dan homogen di atas substrat Si(100) dengan ukuran partikel sekitar 50 nm. Dari pengamatan penampang lintang diperlihatkan bahwa lapisan tipis karbon telah terbentuk di atas substrat Si(100), dengan ketebalan sekitar 100 nm. Karakterisasi sifat listrik dengan LCR meter menunjukkan bahwa nilai konduktansi Fe-C/Si(100) bertambah tinggi seiring dengan penambahan Fe. Karakterisasi sifat magnetik dengan metode Four Point Probe menunjukkan bahwa lapisan tipis Fe-C/Si(100) adalah magnetoresistance positif, dimana seiring dengan peningkatan kandungan Fe pada lapisan tipis Fe-C, nilai resistivitas semakin rendah dan nilai MR semakin meningkat. AbstractCharacterization of electrical and magnetic properties of Fe-C/Si(100) nano composite thin film were carriedout. Carbon nanocomposite and nanostructured with containing iron nanoparticles exhibit electrical andmagnetic properties, so a lot of the electromagnetic field is applied in the form of thin layers. The purpose ofthis study was to observe the electrical and magnetic properties of Fe-C/Si (100) nanocomposite thin layer inthe context of its application in the field of sensors. Fe-C nanocomposites were made by mixing graphite andFe in various weight % of Fe (1 - 3 weight %) using High Energy Milling (HEM) for 50 hours. After mixingpowder of Fe-C were compacted by pressing machine, the pellets were used as a sputtering target for growthof Fe-C nanocomposite thin film on Si(100) substrate. The result observation of SEM shows that the thinfilm has flat and smooth surface, particle of Fe-C was clearly and homogenously deposited on Si(100) withthe particle size of around 50 nm. From cross section observation, it is shown that the graphite thin film hasbeen formed on Si(100) substrate with a thickness of around 100 nm. Characterization of electrical propertyusing LCR meter shows that the conductance value of Fe-C/Si(100) become higher in accordance with theincreasing of Fe. Characterization of magnetic property using Four Point Probe method shows that the Fe-C/Si(100) thin film is a positive magnetoresistance, which in accordance with the increasing of Fe inside theFe-C thin film, the resistivity value become lower and the MR value become higher.

Co-Authors Afifudin Dalimunthe, Afifudin Ahmad Muhtadi Ani Suryanti Astuti - Auri, Mahla Rose Alba Bejo Slamet Budi Utomo D. Ariska, D. Daulay, Achmad T. Desrita Desrita F. F. Rais, F. F. Fadhilah, Amanatul Ifanda, Dayun Junaidy, Adil Kusuma Widya Sari, Kusuma Widya Lestari , Sri Marufi, M. Mashadi Mashadi Mohammad Basyuni muhammad rizky, muhammad Mulyawan, Ade N. Azmi, N. Pesta Saulina Sitohang Putri Pratiwi Ramadhan, Yudha Ilham Rizki, A. Rusdi Leidonald Saeful Yusuf Samosir, Putri Anatasia Sandy, Sarah D. Sihite, Yunita SIREGAR, TESALONIKA Sri Hastuti, Liana Dwi Togar Saragi, Togar Wisnu A. Adi Wisnu Ari Adi Wsinu Ari Adi, Wsinu Ari Yenni Ningsih Siringoringo, Yenni Ningsih Zulheri Noer

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