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ANALISIS STRUKTURMIKRO MAGNET PERMANEN SISTEM NDFEB-SMCO Bonaedy, Taufik A.; Siahaan, Mabe; Manaf, Azwar
Jurnal Sains Materi Indonesia Vol 7, No 1: OKTOBER 2005
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (751.833 KB) | DOI: 10.17146/jusami.2005.7.1.5016

Abstract

ANALISIS STRUKTURMIKRO MAGNET PERMANEN SISTEM NdFeB-SmCo. Telah dilakukan penelitian magnet hibrida berbasis Sm2Co17 dan Nd2Fe14B dengan komposisi 80% Sm(Co,Fe,Cu,Zr)8.5 dan 20% Nd12Fe82B6 (% berat). Proses preparasi pembentukan struktur komposit yang dimaksud adalah melalui teknik konvensional metalurgi serbuk. Proses ball mill dilakukan pada serbuk dengan variasi waktu milling 2 jam sampai dengan 22 jam. Dari serbukmaterial hibrida hasil proses milling ini dilakukan pembuatan magnet hibrida melewati proses sintering dengan suhu sintering 1100 oC, 1130 oC, dan 1160 oC. Studi identifikasi fasa terhadap sampel magnet dengan XRD menunjukkan bahwa fasa magnet utama yaitu Sm2Co17 dan Nd2Fe14B dapat dipertahankan, meskipun telah menjalani proses perlakuan panas. Namun pada sampel magnet hibrida dengan ukuran serbuk semakin halus yaitu hasil penghalusan dengan waktu relatif lama diidentifikasikan fasa oksida berupa Sm2O3, NdO2, Nd2O3. Ditemukan bahwa suhu 1160 oC merupakan suhu pemadatan optimal untuk menjadikan fasa 2/17 sebagai fasa dominan pada sampel magnet hibrida.
PENGARUH HIGH-ENERGYMILLING TERHADAP SIFAT MAGNETIK BAHAN BARIUM HEKSAFERIT (BAO.6FE2O3) Johan, Akmal; Ridwan, Ridwan; Manaf, Azwar; Adi, Wisnu Ari
Jurnal Sains Materi Indonesia Vol 7, No 1: OKTOBER 2005
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (758.879 KB) | DOI: 10.17146/jusami.2005.7.1.5009

Abstract

PENGARUH HIGH-ENERGYMILLING TERHADAP SIFAT MAGNETIK BAHAN BARIUM HEKSAFERIT (BaO.6Fe2O3). Telah dilakukan penelitian mengenai sifat magnetik bahan serbuk barium heksaferit dari pengaruh proses high-energy milling yang diikuti perlakuan annealing pada suhu 1000oC selama 3 jam, masing-masing pengukuran dilakukan pada suhu ruang. Hasil pengukuran pola difraksi sinar-x sebelum dan setelah proses milling 5 jam, 10 jam, 15 jam, 20 jam dan 30 jam terlihat telah terjadi deformasi terhadap struktur kristal yang ditunjukkan dengan tinggi puncak yang semakin menurun dan semakin melebar sehingga didapatkan sifat kemagnetan yang semakin menurun. Dari proses milling didapatkan nilai koersivitas intrinsik 1,68 kOe sebelum proses milling dan 1,13 kOe setelah proses milling 30 jam serta nilai magnetisasi remanen 42,5 emu/gram sebelum proses milling dan 8,16 emu/gram setelah proses milling 30 jam. Namun setelah hasil proses milling disertai perlakukan annealing pada suhu 1000oC selama 3 jamterlihat telah terjadi perbaikan dan penumbuhan struktur kristal yang mengalami deformasi akibat proses milling, dengan ditunjukkan semakin meningkatnya nilai koersivitas intrinsik yaitu 2,09 kOe sebelum proses milling dan 4,39 kOe setelah proses milling 30 jam serta nilai magnetisasi remanen setelah proses milling hingga 30 jam cenderung kembali seperti sebelum proses milling yaitu sekitar 43 emu/gram.
PEMBUATAN MAGNET PERMANEN BARIUM HEKSAFERIT BERBAHAN BAKU MILL SCALE DENGAN TEKNIK METALURGI SERBUK Fiandimas, Arie; Manaf, Azwar
Jurnal Sains Materi Indonesia Vol 5, No 1: OKTOBER 2003
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1345.282 KB) | DOI: 10.17146/jusami.2003.5.1.5206

Abstract

PEMBUATAN MAGNET PERMANEN BARIUM HEKSAFERIT BERBAHAN BAKU MILL SCALE DENGAN TEKNIK METALURGI SERBUK. Telah dilakukan pembuatan fasa magnetik BaO.6(Fe2O3) dari serbuk mill scale yang telah mengalami proses oksidasi dan serbuk BaCO3 melalui teknik powder metallurgy. Berdasarkan pengukuran XRD, mill scale terdiri dari fasa Fe2O3 dan Fe3O4 setelah oksidasi pada suhu 900 °C selama l jam, mill scale menjadi material fasa tunggal Fe2O3 menjadikan material ini sebagai salah satu komponen penyusun senyawa magnetik BaO.6(Fe2O3) untuk pembuatan magnet permanen barium heksaferit. Penghalusan serbuk mill scale dilakukan dengan ball mill. Ditemukan bahwa lama waktu milling l0 jam menghasilkan distribusi ukuran serbuk yang cukup baik < l mm dengan nilai rata-rata ~O,5 ?m mendekati ukuran partikcl berdomain tunggal (0,49 ?m) BaO.6(Fe2O3). Densitas magnet permanen tertinggi yang dicapai melalui tahapan sintering hanya ~78 % dinilai masih terlalu rendah untuk menjadikan sampel sebagai magnet permanen yang baik. Berdasarkan pengukuran magnetisasi sisa (remanen), nilai terukur hanya ~0,4 kG jauh lebih rendah dengan nilai sekarang yaitu l,8 kG. Disimpulkan bahwa meskipun telah berhasil terbentuk fasa magnetik BaO.6(Fe2O3), namun, disebabkan porositas yang relatif tinggi, nilai remanen terukur dari sampel hanya 22 % dari nilai ekspektasi.
Isothermal and non-isothermal crystallization Kinetic behavior of zinc-ferrite formation in theLow temperature flow injection co-precipitation synthesis reactor Sasito, Edie; Soegijono, Bambang; Manaf, Azwar
Jurnal Spektra Vol 14, No 2 (2013): Spektra: Jurnal Fisika dan Aplikasinya
Publisher : Jurnal Spektra

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Abstract

The kinetic behavior of zinc -ferrite crystallization process has been studied by co-precipitation of chlorine salt and alkaline solution. Either the parameter of temperature rate variation, pH previous of reactant and pH alkaline solution results non isothermal process was described by Ozawa equation,. There are significantly deferent in the taking both isothermal and non isothermal data. In the non- isothermal there are just oneexperiment can be sufficiency to reveal any crystal forming parameters but in the isothermal needs several different temperature experiments to reveals the parameter of crystal forming . In this research have be done one time non -isothermal experiment at means temperature 40 0C with temperature increase from 49 0C to 530C, and four time isothermal experiments at means temperature 60 0C,70 0C and 80 0C respectively. The sampling of experiment data have be done effectively using pH real- time video data logger. As a result the energy forming of the zinc ferrite both isothermal and non-isothermal are -4.27kcal/.mol,5.61kcal/mol respectively. The other kinetic parameter of crystallization and crystalline mechanism of both processes will be discussed.Keywords:co-precipitation, zinc-ferrite, non-isothermal process, crystallization, crystalline mechanism, data logger, kinetic behavior, flow injection co-precipitation synthesis.
SINTESIS PIGMEN BESI OKSIDA BERBAHAN BAKU LIMBAH INDUSTRI BAJA (MILL SCALE) Rahman, Tito Prastyo; Sukarto, Agus; Rochman, Nurul Taufiqu; Manaf, Azwar
Jurnal Fisika Vol 3, No 1 (2013)
Publisher : Jurnal Fisika

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Abstract

Limbah industri baja (mill scale) digunakan sebagai alternatif bahan baku pigmen besi oksida. Kajian ilmiah ini menjelaskan proses pembuatan pigmen besi oksida melalui metode presipitasi dengan media air. Pigmen besi oksida yang menjadi target yaitu pigmen kuning goethit ( -FeOOH) dan merah hematit ( -Fe2O3). Goethit diperoleh dengan presipitasi menggunakan amonia dari proses awal terbentuknya ferricssulfat hasil reaksi asam sulfat (H2SO4) dengan limbah mill scale, sedangkan hematit diperoleh dengan proses pemanasan goethit pada temperatur 5000C dan 9000C. Analisa XRD digunakan untuk mengetahui senyawa pigmen yang terkandung dan penggunaan DTA untuk mengetahui pola perubahan fasa akibat proses pemanasan fasa goethit. Analisa warna pigmen menggunakan collorimetri L*a*b System. Warna pigmen yang diperoleh mempunyai tinting strength yang masih kurang dibandingkan dengan pigmen impor.
MICROWAVE ABSORBING PROPERTIES OF LAMN1-X NIXO3. Saptari, Sitti Ahmiatri; Manaf, Azwar; Kurniawan, Budhy
Jurnal Sains Materi Indonesia Vol 15, No 4: JULI 2014
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (230.577 KB) | DOI: 10.17146/jsmi.2014.15.4.4335

Abstract

MICROWAVE ABSORBING PROPERTIES OF LaMn1-x NixO3. The doped lanthanum manganites have unusual magnetic and transport properties, which makes it possible for this material to be used for microwave absorbing. In this study, LaMn1-xNixO3 (x = 0, 0.02, 0.04, and 0.06) were prepared by solid state reaction method as microwave absorption material. The crystal structure and magnetic properties were characterized byX-Ray Diffractometer (XRD) and Vibrating SampleMagnetometer (VSM), respectively. Refinement results of X-Ray diffraction pattern using High Score Plus Software showed that the samples with various x = 0 to x = 0.04 had a single phase with monoclinic crystal structure, while the sample with x = 0.06 had two phases with monoclinic and hexagonal structures. Hysteresis loops showed that the LaMn1-xNixO3 (x = 0, 0.02, 0.04, and 0.06) samples are soft magnetic materials. Microwave absorption properties were investigated in the frequency range of 8-12 GHz using Vector Network Analyzer (VNA). An optimal reflection loss of -8.85 dB is reached at 11.58 GHz for x = 0.04 with sampel thickness of 2 mm.
MATERIAL MAGNETIK BARIUM HEKSAFERIT TIPE-M UNTUK MATERIAL ANTI RADAR PADA FREKUENSI S-BAND Priyono, Priyono; Manaf, Azwar
Jurnal Sains Materi Indonesia Vol 11, No 2: FEBRUARI 2010
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (490.074 KB) | DOI: 10.17146/jusami.2010.11.2.4576

Abstract

MATERIAL MAGNETIK BARIUM HEKSA FERITTIPE-M UNTUK MATERIAL ANTI RADAR PADA FREKUENSI S-BAND.Dalam makalah ini dibahas preparasi dan evaluasi karakteristik senyawa material penyerap (absorber) gelombang mikro dengan komposisi BaFe12-2x MnxTixO19 (x = 0,0 hingga 1,5) yang diperoleh melalui proses subsitusi senyawa dasar barium heksaferit (BaO.6Fe2O3) melalui alur pemaduan mekanik (mechanical alloying). Pembentukan fasa material penyerap diawali dengan substitusi ion Mn dan ion Ti terhadap ion Fe dalam komponen material Fe2O3 pada suhu 1.300 oC. Material hasil substitusi dipadukan secara mekanik dengan komponen BaCO3 untuk membentuk fasa heksaferit tipe-M setelah reaksi padat. Identifikasi puncak difraksi sinar-X dari material hasil pemaduan mekanik ini menunjukkan secara meyakinkan bahwa telah terbentuk material fasa tunggal BaFe12-2x MnxTixO19. Evaluasi material mencakup ukuran rata-rata butir dan karakteristik serapan gelombang mikro pada rentang frekuensi 1 GHz hingga 6 GHz. Hasil evaluasi menunjukkan bahwa terjadi serapan gelombang pada frekuensi ~ 2.000MHz dan ~ 3.500MHz dengan koefisien refleksi yang relatif tinggi pada rentang frekuensi yang tersedia. Keberadaan ion Mn dan ion Ti mampu memperlebar frekuensi serapan terutama pada daerah 3.500 MHz.
Magnetic Field Effects on CaCO3 Precipitation Process in Hard Water Saksono, Nelson; Bismo, Setijo; Krisanti, Elsa; Manaf, Azwar; Widaningrum, Roekmijati
Makara Journal of Technology Vol 10, No 2 (2006)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (154.71 KB) | DOI: 10.7454/mst.v10i2.118

Abstract

Magnetic treatment is applied as physical water treatment for scale prevention especially CaCO3, from hard water in piping equipment by reducing its hardness.Na2CO3 and CaCl2 solution sample was used in to investigate the magnetic fields influence on the formation of particle of CaCO3. By changing the strength of magnetic fields, exposure time and concentration of samples solution, this study presents quantitative results of total scale deposit, total precipitated CaCO3 and morphology of the deposit. This research was run by comparing magnetically and non-magnetically treated&nbsp; samples. The results showed an increase of deposits formation rate and total number of precipitated CaCO3 of magnetically treated samples. The increase of concentration solution sample will also raised the deposit under magnetic&nbsp; field. Microscope images showed a greater number but smaller size of CaCO3 deposits form in magnetically treated samples, and aggregation during the processes. X-ray diffraction (XRD) analysis showed that magnetically samples were dominated by calcite. But, there was a significant decrease of calcite’s peak intensities from magnetized&nbsp; samples that indicated the decrease of the amount of calcite and an increase of total amorphous of deposits. This result&nbsp; showed that magnetization of hard water leaded to the decreasing of ion Ca2+ due to the increasing of total CaCO3 precipitation process.
Effects of Ph on Calcium Carbonate Precipitation Under Magnetic Field Saksono, Nelson; Yuliusman, Yuliusman; Bismo, Setijo; Soemantojo, Roekmijati; Manaf, Azwar
Makara Journal of Technology Vol 13, No 2 (2009)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (187.585 KB) | DOI: 10.7454/mst.v13i2.165

Abstract

Magnetic field effect on CaCO3 precipitation is the key parameter in evaluating the effectiveness of Anti-scale Magnetic&nbsp;Treatment (AMT). The purpose of this study was to investigate magnetic fields influence on CaCO3 precipitation in&nbsp;high and low super-saturated CaCO3 solution by varied pH CaCO3 solution using circulation flow fluid system. The&nbsp;observation results in the high super saturated solution (pH 8.5) showed the increase of precipited CaCO3 in magnetized&nbsp;solutions compared to those in non-magnetic solution during circulation process. In the low super-saturated CaCO3&nbsp;solution (pH 6.4) it was found that magnetic treatment increased CaCO3 precipitation after circulation process. In high&nbsp;super-saturated solution, magnetic field strengthens ion interactions, which reduce precipitation during circulation&nbsp;process. However, in low super-saturated CaCO3 solution, magnetic field weakens hydrate ion interaction which&nbsp;indicated by decreasing of the conductivity of solution. It increases the precipitation of CaCO3 after the circulation of&nbsp;magnetization process has completed.
Formation of CaCO3 Particle and Conductivity of Na2CO3 and CaCl2 Solution Under Magnetic Field on Dynamic Fluid System Saksono, Nelson; Bismo, Setijo; Widaningroem, Roekmijati; Manaf, Azwar
Makara Journal of Technology Vol 15, No 1 (2011)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (157.056 KB) | DOI: 10.7454/mst.v15i1.207

Abstract

Hard&nbsp; water&nbsp; causes&nbsp; the&nbsp; CaCO3&nbsp; scale&nbsp; formation&nbsp; on&nbsp; the&nbsp; pipe&nbsp; walls and&nbsp; heat&nbsp; exchanger&nbsp; equipments&nbsp; in&nbsp; industrial&nbsp; or domestic&nbsp; water&nbsp; processes.&nbsp; A&nbsp; great&nbsp; number&nbsp; of&nbsp; experimental&nbsp; researches&nbsp; on&nbsp; the&nbsp; prevention&nbsp; of the&nbsp; CaCO3&nbsp; precipitation process&nbsp; by&nbsp; magnetic&nbsp; field&nbsp; have&nbsp; been&nbsp; carried&nbsp; out.&nbsp; In&nbsp; this&nbsp; research,&nbsp; Na2CO3&nbsp; and&nbsp; CaCl2&nbsp; solutions&nbsp; was&nbsp; magnetized&nbsp; in&nbsp; the circulated&nbsp; flow&nbsp; condition&nbsp; (dynamic&nbsp; fluid&nbsp; system).&nbsp; The&nbsp; velocity&nbsp; of&nbsp; fluid&nbsp; and&nbsp; the&nbsp; circulation&nbsp; time&nbsp; was&nbsp; modified&nbsp; to examine&nbsp; its influences&nbsp; to&nbsp; the&nbsp; magnetization&nbsp; process.&nbsp; CaCO3&nbsp; content&nbsp; was measured&nbsp; by&nbsp; titration&nbsp; method&nbsp; of&nbsp; EDTA complexometry.&nbsp; Conductivity&nbsp; test&nbsp; was&nbsp; conducted&nbsp; to&nbsp; find&nbsp; out&nbsp; hydrate&nbsp; ion&nbsp; bonding.&nbsp; The&nbsp; results&nbsp; showed&nbsp; that magnetization increased the CaCO3 formation and the optimum process reaches for 10 minutes circulation on 0.554 m/s of flow rate. Magnetic field decreases the conductivities of Na2CO3 and CaCl2&nbsp; solution, hence reduced the ion hydrate bonding. These results showed that magnetization on Na2CO3 and CaCl2 ionic solution was effective in controlling the CaCO3 formation by increasing CaCO3 precipitation.