Articles
<![CDATA[Isothermal and non-isothermal crystallization Kinetic behavior of zinc-ferrite formation in theLow temperature flow injection co-precipitation synthesis reactor ]]>
<![CDATA[Sasito, Edie]]>;
<![CDATA[Soegijono, Bambang]]>;
<![CDATA[Manaf, Azwar]]>
<![CDATA[ Jurnal Spektra Vol 14, No 2 (2013): Spektra: Jurnal Fisika dan Aplikasinya ]]>
Publisher : <![CDATA[Jurnal Spektra ]]>
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<![CDATA[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.]]>
<![CDATA[PHYSICAL CHARACTERISTICS AND MAGNETIC PROPERTIES OF BAFE12O19/SRTIO3 BASED COMPOSITES DERIVED FROM MECHANICAL ALLOYING ]]>
<![CDATA[Widodo, Rahmat Doni]]>;
<![CDATA[Manaf, Azwar]]>
<![CDATA[ Sainteknol : Jurnal Sains dan Teknologi Vol 14, No 2 (2016): December 2016 ]]>
Publisher : <![CDATA[Unnes Journal ]]>
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DOI: 10.15294/sainteknol.v14i2.8994
<![CDATA[Barium hexaferrite and strontium titanate are well established permanent magnet and piezoelectric materials which are technologically and scientifically attractive due to their potential for various applications in the field of magnetic electronics functional materials. However, the material properties for both require a careful control of grain structure as well as microstructure design to meet a specific application. In this work, we report some results of materials characterization especially particles and grains which were promoted during mechanical milling of a BaFe12O19/SrTiO3 composite system. These are including mean particle size characterization by Particle Size Analyzer and mean grain size determination by means of line broadenning analysis employing a step scanning counting in XRD apparatus for composite powders at various milling time up to 60 hours. It was found that the particle size of composite powders initially increased due to laminated layers formation of a composite and then decreased to an asymptotic value of ~8 μm as the milling time extended even to a relatively longer time. However, based on results of line broadening analysis the mean grain size of the particles was found in the nanometer scale. We thus believed that mechanical blending and milling of mixture components for the composite materials has promoted heterogeneous nucleation and only after successive sintering at 1100 oC the milled powder transformed into particles of nanograin. In thireport, microstructure as well as magnetic properties for the composite is also briefly discussed.]]>
<![CDATA[Karakterisasi dan Analisis Struktur Kristal Material Barium Heksaferit dengan Variasi Suhu Annealing ]]>
<![CDATA[Mulyaningsih, Neng Nenden]]>;
<![CDATA[Manaf, Azwar]]>
<![CDATA[ Omega: Jurnal Fisika dan Pendidikan Fisika Vol 2 No 1 (2016) ]]>
Publisher : <![CDATA[Program Studi Pendidikan Fisika UHAMKA ]]>
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<![CDATA[Telah dilakukan penelitian mengenai serbuk material barium heksaferit (BaO.6Fe2O3)} dengan prekursor BaCO3 3,55 gram dan Fe2O3 17,24 gram. Sampel dihaluskan menggunakan high energy milling (HEM) selama 20 jam, kemudian dibuat pelet dengan diameter 2 cm dan ketebalan 0,5 cm. Setelah itu diberi perlakuan pemanasan (annealing) pada suhu yang berbeda yaitu 400oC, 800oC dan 1200oC. Hasil pengukuran pola difraksi sinar-X setelah di-annealing menunjukkan terbentuknya struktur kristal, tetapi variasi suhu tersebut tidak memberikan pengaruh yang berbeda. Dari hasil karakterisasi dengan TGA/DSC, terjadi penurunan massa sekitar 2,05% pada temperatur 160oC - 640oC, akibat menguapnya kandungan air dan pelarut yang terjebak dalam precursor. Penurunan massa juga terjadi pada temperatur 640oC - 875oC sebesar 3,28%, akibat dekomposisi fasa dan transformasi fasa dan puncak eksotermik terjadi pada suhu sekitar 450oC.]]>
<![CDATA[PHYSICAL CHARACTERISTICS AND MAGNETIC PROPERTIES OF BAFE12O19/SRTIO3 BASED COMPOSITES DERIVED FROM MECHANICAL ALLOYING ]]>
<![CDATA[Widodo, Rahmat Doni]]>;
<![CDATA[Manaf, Azwar]]>
<![CDATA[ Sainteknol : Jurnal Sains dan Teknologi Vol 14, No 2 (2016): December 2016 ]]>
Publisher : <![CDATA[Universitas Negeri Semarang ]]>
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DOI: 10.15294/sainteknol.v14i2.8994
<![CDATA[Barium hexaferrite and strontium titanate are well established permanent magnet and piezoelectric materials which are technologically and scientifically attractive due to their potential for various applications in the field of magnetic electronics functional materials. However, the material properties for both require a careful control of grain structure as well as microstructure design to meet a specific application. In this work, we report some results of materials characterization especially particles and grains which were promoted during mechanical milling of a BaFe12O19/SrTiO3 composite system. These are including mean particle size characterization by Particle Size Analyzer and mean grain size determination by means of line broadenning analysis employing a step scanning counting in XRD apparatus for composite powders at various milling time up to 60 hours. It was found that the particle size of composite powders initially increased due to laminated layers formation of a composite and then decreased to an asymptotic value of ~8 μm as the milling time extended even to a relatively longer time. However, based on results of line broadening analysis the mean grain size of the particles was found in the nanometer scale. We thus believed that mechanical blending and milling of mixture components for the composite materials has promoted heterogeneous nucleation and only after successive sintering at 1100 oC the milled powder transformed into particles of nanograin. In thireport, microstructure as well as magnetic properties for the composite is also briefly discussed.]]>
<![CDATA[Microstructures, Magnetic Properties and Microwave Absorption Characteristics of Ti2+ -Mn4+Substituted Barium Hexaferrite ]]>
<![CDATA[Manawan, Maykel]]>;
<![CDATA[Manaf, Azwar]]>;
<![CDATA[Soegijono, Bambang]]>;
<![CDATA[Hercuadi, Asep Yudi]]>
<![CDATA[ Jurnal Elektronika dan Telekomunikasi Vol 14, No 1 (2014) ]]>
Publisher : <![CDATA[Indonesian Institute of Sciences ]]>
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DOI: 10.14203/jet.v14.15-19
<![CDATA[The effect of Ti2+-Mn4+substitution on microwave absorption has been studied for BaFe12-2xTixMnxO19 ferrite, where x varies from 0.2, 0.4, 0.6 and 0.8.Ti2+-Mn4+ ions were obtained from TiO and MnO2 precursors which were mechanically alloyed together with BaCO3 and Fe2O3 precursors. X-ray diffraction (XRD) patterns for sintered samples confirmed that the materials are consisted with single phase BHF structure. Unit cell volume and crystallite size was found increase with increasing x. Crystallite size for all samples below 70 nm, but the grain morphology shown that the grains is in range of 200 - 400 nm, which concluded that each grain are polycrystalline. The saturation magnetization is increases up to x = 0.4 and decrease for higher x values, while the coercivity remains decreases monotonically. These results were interpreted in terms of the site preferential occupation of Ti2+ and Mn4+ at low level substitution.These substitution revealed of enhanced reflection loss (RL) up to 25 dB forx=0.6.It suggested that the synthesized can be employed as effective microwave absorbers in various devices.]]>
<![CDATA[Magnet Nanokomposit Sebagai Magnet Permanen Masa Depan ]]>
<![CDATA[Idayanti, Novrita]]>;
<![CDATA[Manaf, Azwar]]>;
<![CDATA[Dedi, Dedi]]>
<![CDATA[ Metalurgi Vol 33, No 1 (2018): Metalurgi Vol. 33 No. 1 April 2018 ]]>
Publisher : <![CDATA[Pusat Penelitian Metalurgi dan Material - LIPI ]]>
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DOI: 10.14203/metalurgi.v33i1.433
<![CDATA[Naskah ini dibuat berdasarkan kajian literatur tentang penelitian dan pengembangan material magnet permanen terutama pengembangan yang dilakukan oleh para peneliti dalam lebih 100 tahun belakangan. Diketahui bahwa, era magnet permanen modern dimulai pada awal abad ke 19 berlangsung kurang lebih 100 tahun. Dalam 100 tahun kebelakang, ternyata fokus penelitian para peneliti adalah pencarian senyawa magnetik yang potensial. Tidak mengherankan bila dalam periode 100 tahun tersebut berbagai jenis senyawa magnetik berhasil ditemukan. Diawali dengan steel sebagai magnet permanen telah digunakan pada awal abad 19, menyusul kelas-kelas magnetik lainnya seperti alnico, magnet keramik, magnet logam tanah jarang Sm-Co dan terakhir magnet magnet logam tanah jarang Nd-Fe-B dan Sm-Fe-N. Magnet logam tanah jarang Nd-Fe-B ditemukan diujung abad 19 dengan nilai maximum energy product atau (BH)max sebesar 56 MGOe (448 kJ.m-3) telah berhasil diperoleh. Nilai tersebut adalah nilai tertinggi yang pernah dicapai oleh para peneliti sampai saat ini. Namun, penulis mengamati bahwa sejak awal abad 20, ternyata telah terjadi perubahan pada fokus pengembangan penelitian yaitu saat ini tidak lagi berfokus pada pencarian dan penemuan fasa magnetik baru, akan tetapi lebih kepada merekayasa struktur material magnetik melalui penggabungan fasa magnetik keras yang memiliki konstanta magnetocrystalline tinggi dengan fasa magnetik lunak yang memiliki nilai magnetisasi jenuh yang tinggi dalam sebuah struktur komposit sehingga menjadi magnet nanokomposit. Magnet nanokomposit adalah magnet permanen dengan sifat kemagnetan yang lebih unggul dibandingkan dengan magnet konvensional. Keunggulan dimaksud adalah pada nilai magnetisasi remanen (Mr) dan nilai produk energi maksimum (BH)max yang tinggi disebabkan terjadinya efek exchange coupled spring antara fasa maknetik keras dan lunak sehingga mensejajarkan arah magnetisasi kedua fasa magnetik dibawah pengaruh interaksi pertukaran. Para peneliti teoritik pun telah menggali potensi magnet permanen nanokomposit dan menetapkan nilai (BH)max sebesar 1 MJ.m-3 sebagai nilai ultimate yang harus dapat dicapai secara eksperimental. Nilai ultimate tersebut telah membuka tantangan yang besar dan menjadi destinasi baru bagi para peneliti eksperimental. Dalam makalah review ini, disampaikan pengetahuan, penelitian, dan metoda tentang peningkatan sifat kemagnetan material ferit, tanah jarang, dan logam paduan berdasarkan exchan ge interaction mechanism pada saat terjadinya exchange spring magnet antara fasa keras dan fasa lunak.]]>
<![CDATA[PENGARUH MEDIA SUSPENSI TERHADAP PROSES ULTRASONIC MILLING PADA PARTIKEL HYDROMAGNESITE[The Influence of Suspension Media on Ultrasonic Milling Process in Particle Hydromagnesite] ]]>
<![CDATA[Sulistiyono, Eko]]>;
<![CDATA[Manaf, Azwar]]>;
<![CDATA[Firdiyono, F]]>
<![CDATA[ Metalurgi Vol 27, No 2 (2012): Metalurgi Vol. 27 No. 2 Agustus 2012 ]]>
Publisher : <![CDATA[Pusat Penelitian Metalurgi dan Material - LIPI ]]>
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DOI: 10.14203/metalurgi.v27i2.148
<![CDATA[ PENGARUH MEDIA SUSPENSI TERHADAP PROSES ULTRASONIC MILLING PADA PARTIKELHYDROMAGNESITE. Telah dilakukan kegiatan penelitian pembuatan hydromagnesite dengan ukuran butirannanometer dari mineral dolomit, dengan menggunakan media aquabidest, ethanol absolute dan ethylene glycol.Pada penelitian ini bahan baku hydromagnesite diperoleh dari proses ekstraksi dari mineral dolomit melaluiproses kalsinasi parsial, hydrasi dan karbonisasi. Percobaan pertama mencari pengaruh ultrasonik millingterhadap kenaikan temparatur media suspensi dengan tiga media pada konsentrasi 2 % dengan waktu proses 40menit. Hasil percobaan pertama menunjukkan bahwa proses ultrasonic milling yang paling baik adalah denganmedia ethylene glycol . Hal ini dapat dibuktikan dengan adanya kenaikan temperatur dan hasil analisis SEM.Hasil akhir percobaan dapat diperoleh kesimpulan bahwa penggunaan media ethylene glycol mampumenghasilkan partikel ukuran nano dalam bentuk suspensi. Hasil pengukuran dengan Delsa Nano diperoleh hasilterbaik ukuran butiran (23- 95) nm dengan menggunakan pelarut ethylene glycol dan waktu ultrasonic millingadalah 16 menit.AbstractTHE INFLUENCE OF SUSPENSION MEDIA ON ULTRASONIC MILLING PROCESS IN PARTICLEHYDROMAGNESITE . Research activities have been done to make nano size particles of hydromagnesite fromdolomite mineral with ultrasonic milling equipment in the aquabident media or ethanol abosulte media orethylene glycol media. In the research work the raw material of hydromagnesite was obtained from theextraction process of dolomite mineral with partial calcination, hydrationand carbonization processes. The firststep of the process was runin 40 minute. The first experimental result showed that the best contotion ofultrasonic millingprocesswas in the ethylene glycol media. It can be evidenced from the increasing oftemperature and result of SEM anaslysis. The final result can be concluded that in the ethylene glycol media canproduced nano particle size of hydromagnesite e e e in the suspension. Particle size analysis using Delsa Nanoshown that the process wich will held in ethylene glycol media with 16 minute for run time will produce that bestsize (23 – 95) nm.]]>
<![CDATA[EFFECT OF ANNEALING CYCLES ON DEEP DRAWABILITY OF LOW CARBON TITANIUM ADDED STEEL ]]>
<![CDATA[Muda, Iskandar]]>;
<![CDATA[Manaf, Azwar]]>
<![CDATA[ Jurnal Sains Materi Indonesia Vol 21, No 2: JANUARY 2020 ]]>
Publisher : <![CDATA[Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency ]]>
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DOI: 10.17146/jsmi.2020.21.2.5799
<![CDATA[EFFECT OF ANNEALING CYCLES ON DEEP DRAWABILITY OF LOW CARBON TITANIUM ADDED STEEL. Maximum mechanical properties and deep drawability of low carbon titanium added steels was obtained after heat treatment with simulation batch annealing cycles in an industrial process. The effect of holding times and holding temperatures on deep drawability were studied using tensile test for measuring normal anisotropy (r-value) and strain hardening exponent (n-value). Scanning electron microscope were employed for observation of microstructure in steel sheets. X-ray diffraction with pole figure techniques were also used for measuring texture of annealing. Results showed that as the temperature was increased up to 900 oC, both r and n values increased gradually and peaked in the temperature of 850 oC. This results showed that formability of sheet materials increased until batch annealing temperature reach 850 oC as increasing the ratio of intensities {111} /{100}. The largest mean r value of almost 2.6 was obtained in slow heating at holding temperature of 850 oC with n value of ï¾0.27.]]>
<![CDATA[Law of Approach to Saturation for Determining Magnetic Intrinsic Behavior of BaFe12-xMnx/2Tix/2O19 and SrFe12-xMnx/2Tix/2O19 ]]>
<![CDATA[Rafael F Maniur]]>;
<![CDATA[Adam Badra Cahaya]]>;
<![CDATA[Azwar Manaf]]>
<![CDATA[ Al-Fiziya: Journal of Materials Science, Geophysics, Instrumentation and Theoretical Physics Al-Fiziya Journal of Materials Science, Geophysics, Instrumentation and Theoretical Physics Vol.4, N ]]>
Publisher : <![CDATA[Physics Study Programme, Faculty of Science and Technology UIN Syarif Hidayatullah Jakarta ]]>
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DOI: 10.15408/fiziya.v4i2.22206
<![CDATA[The problem with permanent magnetic materials of very high anisotropic fields is that it is still difficult to determine the intrinsic magnetic properties, when measured using a magnetometer which has a limited magnetic field. The Law of Approach to Saturation (LAS) mathematical model provides a way to measure permanent magnets, with high anisotropic fields by correcting the magnetization data of the first quadrant curve or the virgin curve of the minor hysteresis loop. In this research, a computational LAS program was conducted to compute the intrinsic magnetic properties of magnetic materials, such as saturation magnetization, anisotropy field and magnetocrystalline anisotropy constant. Magnetization data were obtained from permagraph measurements of barium hexaferrite (BaFe12O19), strontium hexaferrite (SrFe12O19) and microwave absorbers BaFe12-xMnx/2Tix/2O19 and SrFe12-xMnx/2Tix/2O19. The convergences of magnetization were assessed to determine the effect of substitution on barium hexaferrite and strontium hexaferrite materials on saturation magnetization values, anisotropy constants and anisotropic fields.]]>
<![CDATA[PEMBUATAN MAGNET PERMANEN BARIUM HEKSAFERIT BERBAHAN BAKU MILL SCALE DENGAN TEKNIK METALURGI SERBUK ]]>
<![CDATA[Arie Fiandimas]]>;
<![CDATA[Azwar Manaf]]>
<![CDATA[ Jurnal Sains Materi Indonesia Vol 5, No 1: OKTOBER 2003 ]]>
Publisher : <![CDATA[Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency ]]>
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DOI: 10.17146/jusami.2003.5.1.5206
<![CDATA[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 μm mendekati ukuran partikcl berdomain tunggal (0,49 μm) 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.]]>
