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ANALISIS STRUKTUR MIKRO LAPISAN BOND COAT NIAL THERMAL BARRIER COATING (TBC) PADA PADUAN LOGAM BERBASIS CO Sudiro, Toto; -, Kusnandar; ‘Izzudin, Hubby; Zaini Thosin, Kemas A.
Jurnal Energi Dan Manufaktur Vol 3, No.1 Juni 2008
Publisher : Jurnal Energi Dan Manufaktur

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Abstract

Kehandalan dan umur pakai sistem Thermal Barrier Coating (TBC) ditentukan oleh kestabilan lapisan bond coat dan thermal grown oxide (TGO). Sehingga sangatlah penting untuk memahami mekanisme pembentukan dan degradasi lapisan ini. Pada makalah ini akan dibahas analisis struktur mikro lapisan bond coat NiAl yang dideposisikan pada substrat CoCrNi dengan menggunakan gabungan metoda electroplating dan pack-cementation. Pada makalah ini juga dibahas mekanisme pembentukan void disepanjang interface bond coat¬-substrat setelah tes oksidasi.
EFFECT OF Mn-Ti IONS DOPING AND SINTERING TEMPERATURE ON PROPERTIES OF BARIUM HEXAFERRITE Soehada, Achmad Maulana; Sebayang, Kerista; Sudiro, Toto; Kurniawan, Candra; Sebayang, Perdamean
Jurnal Sains Materi Indonesia Vol 15, No 4: JULI 2014
Publisher : BATAN

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EFFECT OF Mn-Ti IONS DOPING AND SINTERING TEMPERATURE ON PROPERTIES OF BARIUM HEXAFERRITE. Mn-Ti doped (0, 0.1, 0.4, 0.5, and 0.6 mole%-barium hexaferrite powders have been prepared from BaCO3, Fe2O3, TiO2 andMnO powder by mechanical alloying technique for 20 hours. The mixture powder were grinded and then dried at 100 °C for 24 hours, followed by calcined at 1,000 °C for 2 hours. The calcined powder was then crushed into 400 mesh (38 μm) in particle size. X-Ray Diffraction analysis was performed to determine the phase formed. The powder was mixed with 3 wt%Celuna WE -518 polymer, and compressed with applied force of 5 tons. The sintering process was done at temperatures of 1100 °C and 1150 °C for 2 hours. The microstructure of sintered samples was observed by Scanning Electron Microscope - Energy Dispersive X-Ray Spectroscopy (SEM-EDS). The magnetic properties and Reflection Loss (RL) was measured by permeagraph Magnet-Physik and Vector Network Analyzer (VNA), respectively. The results show that the remanance (Br) of samples are likely to decrease with increase in %mol of Mn-Ti and the optimum coercivity (HCJ) 4,42 kOe was achieved at 0,5 mole% Mn-Ti. The maximum reflection loss of -25,6 dB was obtained at 0,4mole%Mn-Ti with sintering temperature of 1100 °C for 2 hours. Accordingly, it can be potentially used for microwave absorption application.
Pelapisan Thermal Barrier Coating (TBC) NiAl pada Paduan Logam Berbasis Co Sudiro, Toto; Tetuko, Anggito Pringgo; Kusnandar, Kusnandar; Thosin, Kemas Ahmad Zaini
Jurnal Fisika dan Aplikasinya Vol 3, No 2 (2007)
Publisher : Jurnal Fisika dan Aplikasinya

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Abstract

Sistem pelapisan material untuk aplikasi temperatur tinggi yang dikenal dengan Thermal Barrier Coating (TBC) telah banyak diaplikasikan pada komponen mesin produksi energi. Sistem ini terdiri atas 4 lapisan: substrat, bondcoat, TGO dan keramik topcoat. Penambahan unsur penguat batas butiran berfungsi untukmeningkatkan ketahanan material terhadap erosi, korosi dan oksidasi sehingga dapat memperpanjang umur pemakaian dan mengurangi biaya operasional. Pada makalah ini akan dibahas pengembangan pelapisan TBC NiAl pada paduan logam berbasis kobalt Co dengan penambahan unsur penguat batas butir menggunakan gabunganmetoda Electro-platting dan Pack-cementation. Hasil pelapisan sebelum dan sesudah tes oksidasi dianalisa dengan SEM, XRD dan EPMA.
Pengembangan Thermal Barrier Coating (TBC) NiCrAl pada Logam Paduan Berbasis Ni untuk Komponen Turbin Gas Kusnandar, Kusnandar; Sudiro, Toto; Tetuko, Anggito Pringgo; I, Diah; Thosin, Kemas Ahmad Zaini
Jurnal Fisika dan Aplikasinya Vol 3, No 2 (2007)
Publisher : Jurnal Fisika dan Aplikasinya

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Abstract

Adanya faktor pengurangan emisi gas dan peningkatan esiensi energi mengakibatkan makin banyaknya masalah kerusakan komponen akibat korosi temperatur tinggi. Sementara ini, bahan yang digunakan untuk pelapisan memiliki kandungan yang berbeda dari substratnya, dan ternyata menimbulkan beberapa masalah seperti terbentuknya topologically closed phase (TCP) yang akan menimbulkan retakan, terjadinya delamination dan terbentuknya permukaan lapisan yang tidak rata. Oleh karena itu, pada penelitian ini dikembangkan TBC NiAl pada substrat berbasis Ni dengan metode gabungan elektroplating dan pack cementation. Penelitian ini terdiri atas deposisi Ni dengan elektroplating dan deposisi Al dengan pack cementation. Setelah itu dilakukan tes oksidasi pada temperatur 1150C. Untuk analisa dan karakterisasi interdifusi elemen lapisan dan substrat dilakukan dengan EPMA.
PREPARASI MAGNET SINTER Pr-Fe-B DENGAN MENGGUNAKAN SPARK PLASMA SINTERING Sudiro, Toto; Sardjono, Priyo; Thosin, Kemas Ahmad Zaini; Muljadi, Muljadi
Telaah Vol 32, No 1 (2014)
Publisher : Research Center for Physics

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Penelitian ini bertujuan untuk mempreparasi sinter Pr-Fe-B dengan teknik spark plasma sintering (SPS). Proses fabrikasi dilakukan di dalam ruang vakum bertekanan kurang dari 60 Pa di mana powder dikompaksi padatekanan 40 MPa pada temperatur yang berbeda: 800 oC, 900 oC, dan 1050 oC. Komposisi fase dari kompak material tersebut dianalisis dengan X-ray diffractometer (XRD Shimadzu-7000TM;). Sampel kemudian dimagnetisasi dengan impulse magnetizer K-series, Magnet-Physik Dr. Steingroever GmbHTM. Hasil penelitian menunjukkan bahwa dengan meningkatnya temperatur SPS, kuat medan magnet permukaannya menurun. Hal ini diduga disebabkan oleh pembentukan Fe phase yang memiliki sifat buruk terhadap properti magnet Pr-Fe-B.
STUDI X-RAY DIFFRACTOMETRY PADA STRUKTUR COATING ALUMUNIUM YANG DIPREPARASI DENGAN METODE MECHANICAL ALLOYING Rosita, Nita; Sudiro, Toto; Aryanto, Didik; Aji, Mahardika Prasetya
Jurnal Sains Materi Indonesia Vol 17, No 1: OKTOBER 2015
Publisher : BATAN

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STUDI X-RAY DIFFRACTOMETRY PADA STRUKTUR COATING ALUMUNIUM YANG DIPREPARASI DENGAN METODE MECHANICAL ALLOYING. Coating alumunium (Al) telah berhasil dideposisikan pada permukaan baja karbon rendah (low carbon steel) dengan menggunakan metode pemaduan mekanik (mechanical alloying). Setelah dideposisikan, coating alumunium diannealing di dalam vacum furnace pada suhu 600 oC, 700 oC dan 800 oC dengan kondisi vakum sekitar 5,6 Pa. Transformasi fasa dan perubahan struktur pada coating alumunium sebagai fungsi suhu annealing dipelajari dengan menggunakan teknik difraksi sinar-X (XRD). Puncak difraksiAl(111) dari hasil karakterisasi XRD mengindikasikan bahwa coating alumunium telah terdeposisi pada permukaan low carbon steel. Selain itu, hasil XRD juga menunjukkan transformasi fasa dan perubahan struktur coating alumunium sebagai efek suhu annealing. Hal itu ditandai dengan munculnya fasa Al3,2Fe, Fe3Al, dan Fe0,8Al0,2 pada pola difraksi XRD setelah diannealing. Peningkatan suhu annealing menyebabkan penurunan d-spacing, parameter kisi dan konstanta kisi kristal Fe0,8Al0,2(110), namun terjadi peningkatan pada regangan kisi dan kerapatan dislokasi. Evolusi pada struktur coating terjadi karena difusi alumunium kedalam low carbon steel.
EFFECTS OF CURING TEMPERATURE AND ATMOSPHERE ON THE PROPERTIES OF ISOTROPIC BONDED NdFeB MAGNETS. Sudiro, Toto; Wismogroho, Agus Sukarto; Sebayang, Perdamean
Jurnal Sains Materi Indonesia Vol 16, No 2: JANUARI 2015
Publisher : BATAN

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EFFECTS OF CURING TEMPERATURE AND ATMOSPHERE ON THE PROPERTIES OF ISOTROPIC BONDED NdFeB MAGNETS. The purpose of this paper was to synthesize the isotropic bonded NdFeB magnets at varying curing temperature and atmosphere, and to clarify their properties. For the aforesaid objective, the NdFeB powder was mixed with polyacrylate binder (3wt%) and compacted by hydraulic pressure with a compressive pressure of 30 MPa. The specimens were then separately cured at 100, 150, 180 and 200°C for 1 h in air and vacuum. The effects of curing temperature in air and vacuum on the bulk density and magnetic properties of isotropic bonded NdFeB magnets were studied. The results indicated that the bulk density and fluxmagnet density of bonded NdFeB magnets decreased with increase in curing temperature. This seems to be due to the binder vaporization and oxidation of element of NdFeB magnet. The bulk density of specimens cured in air was higher than that in vacuum for all temperatures. On the contrary, the magnetic flux density showed the opposite behavior. The optimum magnetic properties were achieved at curing temperature of 100oC for 1 h in vacuumwith Br = 6,61 kG, HCJ = 8,841 kOe, and BHmax = 9,01 MGOe.
CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN RECYCLE PROCESS Wismogroho, Agus Sukarto; Widayatno, Wahyu Bambang; Sudiro, Toto; Aryanto, Didik
Jurnal Sains Materi Indonesia Vol 16, No 3: APRIL 2015
Publisher : BATAN

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CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN RECYCLE PROCESS. In general, during its fabrication, 2-5%of total products of Ba-Sr hexaferrite permanent magnet will be rejected.Accordingly, an increase in rejected product of permanent magnet needs to be considered. It is expected that the re-utilization of rejected product can increase the production efficiency in order to achieve zero waste-production. In the present work, the recycling process of Ba-Sr hexaferrite permanent magnet was studied by applying 1 T magnetic field (anisotropic) to align the powder. The rejected products were milled using shaker mill PPF-UG for 10-40 min and then sintered at 1200 ºC for 60 min. The results show that the remanence of original powder was increased by 50% after the particle orientation. However, the recycled sample doesn’t show a significant different. SEM and XRD analysis show the crystalline structure transformation from symmetrical hexagonal to asymmetrical hexagonal structure with crystalline growth in a-b axis direction. This transformation leads to lost in its magneto crystalline anisotropy. Therefore, it was difficult to align the particle.
STRUCTURE AND HARDNESS CHARACTERISTICS OF 50Cr-50Al COATING PREPARED BY A MECHANICAL ALLOYING TECHNIQUE: EFFECTS OF HEAT TREATMENT TEMPERATURE Sudiro, Toto; Sebayang, Perdamean
Teknologi Indonesia Vol 38, No 3 (2015)
Publisher : LIPI Press

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In the present work, a mechanical alloying technique was used to prepare 50Cr-50Al (in atomic, at %) coating on the surface of low carbon steel. The coated samples were then annealed in a vacuum at elevated temperatures of 600, 700, 800, and 900C for 2h, separately. The effects of annealing temperature on the structure characteristic of 50Cr-50Al coating were studied by XRD and SEM-EDX, and coating hardness was measured by micro-Vickers hardness test. The results showed that the annealing process led to the formation of inter-metallic phases and interdiffusion of Fe element from the substrate and Cr, Al elements from the coating, depending on annealing temperature. As annealing temperature increased to 900C, however, X-ray diffraction analysis indicated the formation of Al2O3. Meanwhile, the hardness of cross-sectional of coating increased after annealing at 600C. The coating hardness decreased as annealing temperatures increased.
THE EFFECT OF ZnO ADDITIVE ON PHYSICAL PROPERTIES AND MICROSTRUCTURE OF BaFe12O19 MAGNETIC MATERIAL Sebayang, Perdamean; Sudiro, Toto; Aryanto, Didik; Nugraha, Endra
Teknologi Indonesia Vol 39, No 2 (2016)
Publisher : LIPI Press

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Preparation of BaFe 12 O 19 powder containing varying amount of ZnO as 5, 10, 15 and 20 % by mass were prepared by a high energy milling (HEM) for 1 hour and compacted into a pellet using 80 kgf/cm 2 in compressive pressure. The samples were sintered at elevated temperatures of 800 and 1,000 o C for 2 hours, separately. The characterization results indicated that BaFe 12 O 19 -10 mass % ZnO exhibits excellent in physical and magnetic properties that can be potentially used for recording media and microwave absorbing material applications.