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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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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.

PHYSICAL CHARACTERISTICS AND MAGNETIC PROPERTIES OF BAFE12O19/SRTIO3 BASED COMPOSITES DERIVED FROM MECHANICAL ALLOYING Widodo, Rahmat Doni; Manaf, Azwar
Sainteknol : Jurnal Sains dan Teknologi Vol 14, No 2 (2016): December 2016
Publisher : Unnes Journal

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v14i2.8994

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 Î¼m 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.

Karakterisasi dan Analisis Struktur Kristal Material Barium Heksaferit dengan Variasi Suhu Annealing Mulyaningsih, Neng Nenden; Manaf, Azwar
Omega: Jurnal Fisika dan Pendidikan Fisika Vol 2 No 1 (2016)
Publisher : Program Studi Pendidikan Fisika UHAMKA

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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.

PHYSICAL CHARACTERISTICS AND MAGNETIC PROPERTIES OF BAFE12O19/SRTIO3 BASED COMPOSITES DERIVED FROM MECHANICAL ALLOYING Widodo, Rahmat Doni; Manaf, Azwar
Sainteknol : Jurnal Sains dan Teknologi Vol 14, No 2 (2016): December 2016
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v14i2.8994

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 Î¼m 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.

Perolehan Tio2 Dari Iron Ore Mengandung Titanium Melalui Proses Reduksi Karbon Dan Pelarutan Asam Rayhana, Elda; Manaf, Azwar
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 2, No 02 (2012): IJAP VOLUME 02 ISSUE 02 YEAR 2012
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v2i02.1288

REDUCTION AND LEACHING PROCESSES. Indonesia has a large source of iron oreÂ which is quite tempting for the purposes of exploitation in form of raw materials as well asÂ for the production of pig iron. However, not all sources of iron ore are proved useful sinceÂ not only because the present of deposit is scattere dinamounts of less significant but alsoÂ because it contains element of tin oxide compounds with iron like ilmenite or FeTiO3.Â However,ilmenite can actually be used as a source of titanium metal which is much moreÂ valuable than Fe it self. In order to recover the Ti from their respective compound it isÂ required the release of strong bonds between the atoms in the compound. This paper reportsÂ the recovery of Ti oxide of ilmenite containing iron ore which was obtained through aÂ combination of carbon reduction and acid leaching processes. Carbon reduction of iron oreÂ was carried out through mechanical milling between iron ore and carbon with a ratio of 1:1.Â This was successively followed by a sintering at a temperature of 1000 oC employing aÂ heating rate of 10 Â° C/min for 0-3 hours. The reduction process has resulted in theÂ formation of 27.83wt% TiO2. In order to improve the recovery level of TiO2, furtherÂ reduction process was conducted through an HCl leaching. This successive stage producedÂ fine powders in the form of deposits. Based on our quantitative analysis, the recovery ofÂ TiO2 increased to a level of 73.73%.

Pengaruh Substitusi Ion Mn dan Ion Co Serta Ion Ti pada Pembentukan Fasa dan Sifat Magnetik Barium Hexaferrite BaFe9(MnCo)1,5Ti1,5O19 Disintesis Melalui Rute Metallurgi Serbuk P, Priyono; Siradj, Eddy; Manaf, Azwar
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 3, No 01 (2013): IJAP VOLUME 03 ISSUE 01 YEAR 2013
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v3i01.1310

Barium ferrite with hexagonal molecular BaFe12O19 is well-known for its high performanceÂ permanent magnetic and good mechanical properties and attracted attention of researchers forÂ a long time. The hexaferrite powders were produced according to a conventional ceramicÂ process with powder metallurgy method. Moreover, the powders were analyzed by X-rayÂ diffraction, to detect the presence of secondary phases. The magnetic properties of the sampleswere measured at room temperature using Permeagraph with a maximum applied field of 1.5Â T. The calculation of the lattice parameter on conventional magnets (BaFe12O19) results a = b =Â 5,894 Ã… and c = 23,210 Ã…, while the substituted phase has a range value of a = b betweenÂ 5,893 Ã… to 5,899 Ã…, and c lattice parameter value is in the range of 23,328 ËšA to 23,346 Ã….With the partial substitution of Fe+3 ions by Mn+2 ions, ion Co+2 and Ti+4 ion magneticÂ properties decrease primarily on the magnetic coercivity from 125 kA / m (conventional) to ~ 5Â kA /m in the substituted materials.

Microstructures, Magnetic Properties and Microwave Absorption Characteristics of Ti2+ -Mn4+Substituted Barium Hexaferrite Manawan, Maykel; Manaf, Azwar; Soegijono, Bambang; Hercuadi, Asep Yudi
Jurnal Elektronika dan Telekomunikasi Vol 14, No 1 (2014)
Publisher : Indonesian Institute of Sciences

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.

Magnet Nanokomposit Sebagai Magnet Permanen Masa Depan Idayanti, Novrita; Manaf, Azwar; Dedi, Dedi
Metalurgi Vol 33, No 1 (2018): Metalurgi Vol. 33 No. 1 April 2018
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

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.

PENGARUH MEDIA SUSPENSI TERHADAP PROSES ULTRASONIC MILLING PADA PARTIKEL HYDROMAGNESITE[The Influence of Suspension Media on Ultrasonic Milling Process in Particle Hydromagnesite] Sulistiyono, Eko; Manaf, Azwar; Firdiyono, F
Metalurgi Vol 27, No 2 (2012): Metalurgi Vol. 27 No. 2 Agustus 2012
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

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.

EFFECT OF ANNEALING CYCLES ON DEEP DRAWABILITY OF LOW CARBON TITANIUM ADDED STEEL Muda, Iskandar; Manaf, Azwar
Jurnal Sains Materi Indonesia Vol 21, No 2: JANUARY 2020
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

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.

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