PEMBUATAN DAN KARAKTERISASI Α-FE2O3 BERBASIS LIMBAH BAJA MILL SCALE DENGAN ADITIF FeMo

Preparation and characterization of α-Fe2O3-based onsteel waste of mill scale with the addition of 1, 3, 5, 7 and wt%FeMo based on natural materials have been successfully carried out. The process of mixing the o powder of mill scale and FeMo performed using HEM. Then the mix powder calcined at temperature of 900C (2 hours). Characterization of XRD shows have been formed phase of α-Fe2O3 (hematite). The calcined material o compacted (70 kgf / cm2) and sintered at temperature of 1250C. Characterization XRD showed a single phase of hematite (α-Fe2O3).Characterizationof VSM shows a decrease in coercivity and increase in saturation along with the increase FeMo are added. Keywords : α-Fe2O3, mill scale, FeM

Pembuatan dan Karakterisasi Mullite Berbasis Abu Vulkanik dan Alumina

Telah berhasil dibuat keramik berbasis mullite dari abu vulkanik dan Al2O3 dengan metode paduan mekanik dan sintering. Preparasi dimulai dengan proses milling abu vulkanik dan Al2O3. Ukuran diameter rata-rata serbuk hasil milling diperoleh nilai 3,54 µm. Serbuk hasil milling kemudian dikompaksi dan disinter dengan variasi suhu 900, 1000 dan 1100 °C. Hasil uji densitas dan porositas menunjukkan bahwa semakin tinggi suhu sintering maka nilai densitas akan semakin tinggi sedangkan porositasnya semakin rendah. Hasil analisa XRD menunjukkan bahwa terdapat tiga fasa sampel yaitu mullite sebagai fasa dominan serta hematit dan SiO2 sebagai fasa sekunder. Hasil nilai kekerasan sampel menunjukkan bahwa semakin tinggi suhu sintering maka nilai kekerasannya juga semakin tinggi. Nilai optimum sampel diperoleh pada sampel yang disinter pada suhu 1100 °C dengan nilai densitas, porositas dan kekerasan masing-masing sebesar 2,54 g/cm3, 5,21% dan 283,16 HV

Sintesis Nanopartikel Cobalt Ferrite (CoFe2O4) dengan Metode Kopresipitasi dan Karakterisasi Sifat Kemagnetannya

Magnetic nanoparticles of cobalt ferrite (CoFe2O4) have been synthesized by co-precipitation method with various synthesis temperature and concentration of NaOH. The structural characteristics and particle size of CoFe2O4 were determined by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM), its showed that nanoparticles well crystallized with various grain size which depend on synthesis parameters. The grain sizes estimated using the Scherrer formula were found that the grain size increased with increasing temperature synthesis and decreasing concentration of NaOH. Magnetic characterization of CoFe2O4 nanoparticles was investigated by using a Vibrating Sample Magnetometer (VSM). Sample with various concentration of NaOH showed that coercivity was decrease with the decrease of particle size. In other hand, samples with various synthesis temperature found that sample with smallest grain size have high coersivity. The saturation magnetization increase when crystallinity increase. Based on the results, it can be concluded that magnetic characterization of CoFe2O4 was influenced by grain size and crystallinity. Keywords: nanoparticles, CoFe2O4, co-presipitation Nanopartikel magnetik Cobalt Ferrite (CoFe2O4) telah berhasil disintesis dengan metode ko- presipitasi dengan memvariasi parameter suhu dan konsentrasi NaOH. Struktur dan ukuran par- tikel hasil analisa X-Ray Diffraction (XRD) dan Transmission Electron Microscopy (TEM) menunjukkan bahwa nanopartikel mengkristal dengan baik dan ada ketergantungan ukuran bu- tir nanopartikel terhadap dua variasi parameter sintesis tersebut. Ukuran butir yang dihitung menggunakan persamaan Scherrer menunjukkan bahwa ukuran butir meningkat seiring pen- inggkatan suhu dan berkurangnya konsentrasi NaOH. Sifat kemagnetan CoFe2O4 hasil analisa Vibrating Sample Magnetometer (VSM). Sampel dengan variasi konsentrasi NaOH, semakin kecil ukuran butir nanopartikel, medan koersivitasnya semakin rendah. Sementara untuk sam- pel dengan variasi suhu, semakin kecil ukuran butir, medan koersivitasnya semakin tinggi. Ha- sil VSM juga menunjukkan bahwa semakin tinggi kristalinitas sampel, nilai magnetisasi satu- rasinya semakin tinggi. Dengan demikian dapat disimpulkan bahwa ukuran butir dan kristalini- tas mempengaruhi sifat kemagnetan nanopartikel CoFe2O4. Kata kunci: nanopartikel, CoFe2O4, kopresipitas

MICROSTUCTURES AND MAGNETIC PROPERTIES OF BaFe12O19 WITH MgO-Al2O3 ADDITIVES

Barium hexaferrite (BaFe12O19) is a permanent magnet material known as a hard magnet. Microstructures and magnetic properties of MgO-Al2 O3 (0.3 0.9; and 1.5 % mole) addition in BaFe12O19 have been investigated. The mixing powders of Barium Hexaferrite have been prepared by the mechanical alloying method. Particle sizes of the mixing powder show that the particle size increases with the higher concentration of MgO-Al2 O3 additives. The mixing powders are compacted into pellets and sintered with temperatures of 1,100 and 1,200 °C for 2 hours. Herein, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) results show that the samples have a hexagonal structure, and their sizes and shapes are not homogeneous. Hardness values linearly decrease with the increasing of MgO-Al2 O3 (908.58 to 531.81 HV) comparable with bulk density measurements (4.85 to 4.52 g/cm2 ). On the other hand, Paragraph and Gaussmeter measurement shows a decreasing trend as the MgO-Al2 O3 additives content increased. Flux density results decline from 816.00 to 706.20 G, then magnetic remanence decreases from 2.29 to 1.92 kG and saturation magnetization drops from 3.44 to 2.93 kG. In addition, coercivity decreases from 3.83 to 2.52 kOe in proportion to the increasing of sintering temperature

EFEK ADITIF FeMo DAN PROSES KALSINASI PADA SERBUK MAGNETIK BaFe12O19

Pada penelitian ini, telah dilakukan investigasi efek aditif FeMo dan proses kalsinasi pada pembuatan magnet permanen bariumheksaferit (BaFe12O19). Proses pembuatan magnet bariumheksaferit dilakukan denganmetode mechanical alloying. Serbuk hasil mixing antara BaFe12O19dan FeMo dikalsinasi dengan variasi suhu kalsinasi 1000 oC dan 1200 oC. Karakterisasi yang dilakukan meliputi sifat fisis dan magnetik, dengan menggunakan X-Ray Diffraction (XRD) dan piknometeruntuk mengetahui fasa dan nilai densitas magnet, serta menggunakanVibrating SampleMagnetometer (VSM) pada pengukuran sifatmagnetikmagnet bariumheksaferit. Dari hasil eksperimen, dapat diketahui bahwa penambahan aditif FeMo dapat menaikkan nilai densitas pada serbuk bariumheksaferit. Hasil analisis sifat magnetik, dapat diketahui bahwa penambahan aditif FeMo secara keseluruhan menurunkan sifat magnetik magnet. Namun penambahan %wt FeMo menaikkan nilai remanensi, saturasi dan energi produk maksimum (BHmax) magnet barium heksaferit, meskipun nilai koersivitas magnet tetap menurun. Sedangkan kenaikan suhu kalsinasi mampu menaikkan nilai remanensi, dan BHmax, namun menurunkan nilai koersivitas dan saturasi dari magnet barium heksaferit. Hal ini menunjukkan penambahan zat aditif FeMo mampu mengubah struktur material magnet permanen barium heksaferit dari hard magnetik menjadi soft magnetik material. Nilai optimumdihasilkan pada komposisi penambahan 5 %wt aditif FeMo dengan nilai densitas serbuk 3,71 g/cm3 sebelum dikalsinasi, dan memiliki sifat magnetik seperti: saturasi 2,12 kG, remanensi 1,15 kG, koersivitas 0,45 kOe dan BHmax0,145 MGOe setelah dikalsinasi pada suhu 1000 oC

Characteristic of microstructure and magnetic properties in LaFeO3 using co-precipitation method

Abstrak. Perkembangan penelitian material ferit memiliki karakteristik mikrostruktur dan sifat magnetik yang berbeda-beda. Karakteristik mikrostruktur dan sifat magnetik dari Fe3O4 dan LaFeO3 telah berhasil dilakukan menggunakan metode ko-presipitasi lanthanum klorida dan pasir besi alam digunakan sebagai prekursor untuk preparasi sintesis nanopartikel Fe3O4 LaFeO3. Rasio molar antara lanthanum klorida dan pasir besi alam adalah 1:1, dan tanpa lanthanium. Karakterisasi sampel menggunakan XRD, SEM dan VSM. Hasil XRD menunjukkan bahwa kedua sampel telah memiliki fase tunggal tanpa pengotor kristal seperti La2O3 atau Fe2O3. Hasil morfologi SEM menunjukkan bahwa Fe3O4 dan LaFeO3 memiliki ukuran partikel yang random. Histogram distribusi sebaran partikel untuk kedua sampel ini menunjukkan range 50-300 nm. Sifat magnetik dari sampel Fe3O4 memiliki Ms= 20 emu/g, Mr= 9 emu/g dan H= 400 Oe, sedangkan sifat magnetik LaFeO3 yaitu Ms= 10 emu/g, Mr= 8 emu/g dan H= 410 Oe. Hasil mikrostruktur dan sifat magnetik dalam penelitian ini dapat mendukung dalam pembuatan magnet permanen.  Abstract. The development of research on ferrite materials has different microstructural characteristics and magnetic properties. The microstructural characteristics and properties of Fe3O4 and LaFeO3 have been successfully carried out using the co-precipitation method. Lanthanum chloride and natural iron sand were used as precursors for the preparation of the synthesis of Fe3O4 LaFeO3 nanoparticles. The molar ratio between lanthanum chloride and natural iron sand is 1:1, and without lanthanium. Sample characterization using XRD, SEM and VSM. The XRD results show that the second sample already has a single phase without crystal impurities such as La2O3 or Fe2O3. SEM morphology results show that Fe3O4 and LaFeO3 have random particle sizes. Histograms of particle distribution distribution for these two samples show the range of 50-300 nm. The nature of the sample Fe3O4 has Ms= 20 emu/g, Mr= 9 emu/g and H= 400 Oe, while the specific properties of LaFeO3 are Ms= 10 emu/g, Mr= 8 emu/g and H= 410 Oe. The results of the microstructure and magnetic properties in this study can support the manufacture of permanent magnet

Study and characterization of Fe3O4 synthesized from natural iron sand in Sumatera Utara

Abstrak. Pasir besi alam adalah satu dari sumberdaya alam di Indonesia, khususnya Sumatera Utara, yang pemanfaatannya belum dilakukan secara optimal. Penelitian ini dilakukan untuk menganalisis kandungan dan ukuran butir Fe yang terdapat di Provinsi Sumatera Utara. Pembuatan sampel pasir besi alam ini menggunakan metode milling basah yang dikeringkan pada suhu 100oC hingga sampel menjadi serbuk. Selanjutnya, proses ekstrasi menggunakan magnet permanen dilakukan pada sampel pasir untuk memisahkan material magnetik dan non magnetik didalamnya. Sampel magnetik yang diperoleh kemudian diuji menggukan alat XRD, SEM-EDX dan VSM. Hasil XRD menunjukkan bahwa sampel pasir besi alam memiliki fasa tunggal yaitu fasa magnetite (Fe3O4), dan struktur kristal kubik spinel yang mana a = b = c = 8.513 Ǻ. Berdasarkan hasil SEM-EDX, terdapat kandungan unsur Fe dan O didalam pasir besi, yang berasal dari fase Magnetit (Fe3O4), maghemite (γ-Fe2O3) dan hematit (α-Fe2O3). Hasil VSM menunjukkan bahwa parameter sifat magnetik saturasi (Ms) sebesar 30.52 emu.g-1, magnetik remanansi (Mr) sebesar 21.66 emu.g-1 dan koersivitas sebesar 455.17 Oe. Hasil studi ini berpotensi dalam pengolahan material magnetik lainnya sehingga dapat ditindaklanjuti dalam pembuatan material berikutnya dalam aplikasi bidang tertentu. Abstract. Natural iron sand includes one of the natural resources in Indonesia, especially in Sumatera Utara which has not been used optimally. The study was done to investigate the content and grain size of Fe found in Sumatera Utara. The manufacture of this natural iron sand sample uses the wet milling method which is dried at 100oC until the sample becomes powder. Next, the extraction process using permanent magnet was performed on the sand sample to separate its magnetic and non-magnetic materials. The iron sand was tested via XRD, SEM-EDX and VSM. The XRD results reveal that the natural iron sand sample has a single phase of magnetite (Fe3O4) phase, and a spinel cubic crystal structure with a = b = c = 8.513 Ǻ. SEM-EDX results show that the iron sand sample consists of Fe and O components, which come from Magnetite (Fe3O4), Maghemite (γ-Fe2O3) and hematite (α-Fe2O3) phases. The VSM results show that the saturation type (Ms) parameter is 30.52 emu.g-1, remanence type (Mr) is 21.66 emu.g-1 and coercivity is 455.17 Oe. The study’s results are potential in other making magnetic materials, so that they can be followed up in the manufacture of subsequent materials in certain applications, respectively

Preparation and characterization of ZnFe2O4 on the microstructures and magnetic properties

Abstrak. Telah berhasil dilakukan sintesis ZnFe2O4 menggunakan metode sol-gel. ZnO dan serbuk Fe3O4 dicampur dan dipanaskan menggunakan hotplate pada suhu 60oC selama satu jam. Efek dari doping ZnO pada mikrostruktur, morfologi dan sifat magnet dikarakterisasi menggunakan XRD, SEM dan VSM. Hasil dari XRD dan SEM mengkonfirmasi bahwa struktur ZnFe2O4 spinel ferit menunjukkan kristal rata-rata 1 μm. Kemudian sifat kemagnetan ZnFe2O4 yang dikonfirmasi bersifat paramagnetik dengan kondisi optimum dari sifat kemagnetan tersebut tercantum sebagai berikut: Ms 0.4 emu×g-1, Mr 0.2 emu×g-1, dan Hc 230 Oe.Abstract. ZnFe2O4 have been synthesized using sol-gel method. ZnO, and Fe3O4 powder was mixing with hotplate for one hour in 60oC. Effect of ZnO doped on microstructure, morphology and magnetic properties were investigated using XRD, SEM and VSM. The result of XRD and SEM confirmed that the ZnFe2O4 structure of spinel ferrite has average crystal of 1 μm. The magnetic properties of ZnFe2O4 confirmed paramagnetic with the optimum condition of the magnetic properties are listed in the following: Ms 0.4 emu×g-1, Mr 0.2 emu×g-1, and Hc 230 Oe.Keywords: ZnFe2O4, Sol-gel method, Microstructures, Magnetic Properties

FABRIKASI DAN KARAKTERISASI STRUKTUR KRISTAL DAN SIFAT KEMAGNETAN NANOPARTIKEL COBALT FERRITE (CoFe2O4) BESERTA PROSES FUNGSIONALISASINYA DENGAN PEG-4000

Magnetic nanoparticles of Cobalt Ferrite (CoFe2O4) have been synthesized by co-precipitation method with various synthesis temperatures, concentration of NaOH and stirring duration. The structural characteristics and particle�s size of CoFe2O4 were determined by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM), it showed that nanoparticles well crystallized with various grain size which depend on those synthesis parameters. The grains size estimated using the Scherrer formula were found that the grain size increased with increasing synthesis temperature, decreasing concentration of NaOH and decreasing stirring duration. Magnetic properties of CoFe2O4 nanoparticles analized by Vibrating Sample Magnetometer (VSM) showed that coercive field was decrease with the decreasing of particle size. But it is not for sample 8,844 and 8,898 nm because of agglomeration effect. The saturation and remanent magnetization increased with the increasing degree of crystallinity. But it also depends on presence of α-Fe2O3 phases and their grain size. Based on magnetic characterization analysis sample have been chosen with temperature 80°C, concentration of NaOH 5 M and stirring duration 120 minutes to modified with PEG-4000. XRD and TEM analysis showed that modification with PEG- 4000 given increasing degree of crystallinity, decreasing agglomeration and controlled shape to more spherical. VSM analysis showed that modification with PEG-4000 given decreasing saturation was predicted because of α-FeO(OH) and γ-FeO(OH) phases from bonds at interface of CoFe2O4 with PEG-4000 which shown at XRD and Furrier Transform Infra Red (FTIR) analysis

Efek Penambahan Fe3Mn7 Terhadap Sifat Fisis dan Mekanik α-Fe2O3

Abstrak: Preparasi dan karakterisasi pellet α-Fe2O3 dengan penambahan 0, 2, 5 dan 10 %wt. Fe3Mn7 berbasis pada materialalam telah berhasil dilakukan. Proses pencampuran serbuk α-Fe2O3 dan Fe3Mn7 dilakukan dengan menggunakan HEM. ºKemudian campuran serbuk dikasinasi pada suhu 1000C, dikompaksi pada 69 Pa hingga menjadi pellet dan disinter padasuhu 1000 ºC. Karakterisasi XRD menunjukkan adanya fasa dominan α-Fe2O3 dan fasa baru MnO2 dan Fe3O4. Densitas dankekerasan sampel meningkat secara linier seiring dengan kenaikan komposisi Fe3Mn7 yang ditambahkan. Sampel optimum3diperoleh pada sampel α-Fe2O3/10 %wt. Fe3Mn7 dengan nilai bulk density dan kekerasan masing-masing 4,98 g/cm and994,94 HV. Sampel ini termasuk dalam klasifikasi hard magnet dengan nilai magnetisasi saturasi, remanen dan koersivitasmasing-masing sebesar 24,0 emu/g, 10,3 emu/g dan 571,8 Oe.Kata kunci:. α-Fe2O3, Fe3Mn7, densitas, kekerasan, sifat magnetikAbstract: Preparation and characterization of α-Fe2O3 pellet with the addition of 0, 2, 5 and 10 %wt. Fe3Mn7 based on naturalmaterials have been successfully carried out. The process of mixing powder of α-Fe2O3 and Fe3Mn7 was performed usingºHEM. Then, the mix powders were calcined at temperature of 1000 C. After that, the powders were compacted at 69 Pa intopellet and sintered at temperature of 1000ºC. Characterization of XRD shows that the samples have major phase of α-Fe2O3and new phases of MnO2 and Fe3O4. The density and hardness samples increase linearly with increasing of Fe3Mn73composition. The optimum sample with α-Fe2O3/10 %wt. Fe3Mn7 has bulk density and hardness value of 4.98 g/cm and 994.94HV respectively. This sample is classified as semi-hard magnet with magnetization saturation, remanence and coercivity valueof 24.0 emu/g, 10.3 emu/g dan 571.8 Oe respectively.Keywords: α-Fe2O3, Fe3Mn7, density, hardness, magnetic propertie