Pudji Untoro
Pusat Teknologi Bahan Industri Nuklir (PTBIN)-BATAN Kawasan Puspiptek, Serpong 15314, Tangerang Selatan

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Transmission Electron Microscopy Characterization of High-Temperatur Oxidation of Fe-20Cr-5Al Alloy Prepared by Focused Ion Beam Technique Dani, Mohammad; Untoro, Pudji; Panca Putra, Teguh Yulius Surya; Parikin, Parikin; Mayer, Joachim; Dimyati, Arbi
Makara Journal of Technology Vol 19, No 2 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (397.594 KB) | DOI: 10.7454/mst.v19i2.3141

Abstract

The Focused Ion Beam (FIB) technique was applied for cross section preparation of the oxidized alloy for Transmission Electron Microscopy (TEM) study. Prior to preparation, the specimens of Fe-20Cr-5Al alloy sheet were oxidized in air at 1200 oC for 2 minutes, 10 minutes, 2 hours, and 100 hours. The microstructure and elemental composition of the samples were characterized using TEM equipped with an Energy Dispersive X-Ray Spectroscopy (EDX). The Electron Energy Loss Spectroscopy (EELS) was used to determine of the light elements. The TEM investigation reveals remarkable microstructure evolution of the specimens during oxidation which generally exhibit a typical multi-layer structure. The TEM images, however, can provide detailed description about the phases occur after oxidation such as the Tungsten (W) and the Gallium (Ga) layers on top of the samples obviously formed during FIB preparation, the formation of Al2O3 and Cr2O3 layer, MgAl2O4 spinel, porosity, Zr/Hf/Mg phases or clusters inside the oxide scale. Hence, the FIB technique has been proven to be reliable preparation technique for microstructural and elemental studies of Fe-20Cr-5Al alloy using TEM.
Esterification of Waste Cooking Oil Using Ultrasonic: Kinetic Study Agustian, Egi; Jessica, Jessica; Untoro, Pudji; Sulaswatty, Anny
Jurnal Kimia Terapan Indonesia (Indonesian Journal of Applied Chemistry) Vol 20, No 2 (2018)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (521.053 KB) | DOI: 10.14203/jkti.v20i2.397

Abstract

Waste cooking oil (WCO) have a great potential as an alternative raw material for producing biodiesel. The literatures kinetic of the esterification of WCO in the presence of phosphoric acid catalyst with ultrasonic assisted are rare and most literatures used conventional method. This study aims to determine the optimum condition and the parameters of first and second order kinetics of the WCO esterification which was assisted by ultrasonic bath. Variables that used in this study are methanol/oil mole ratio, acid catalyst concentration and reaction temperature. The highest conversion was 42.08% with methanol/oil mole ratio of 15:1, a catalyst (phosphoric acid) concentration of 9% wt and temperature of 50oC within 90 minutes. The reaction time was reduced to 3 times (minute) compare to conventional method and fatty acid reduced 42%. Kinetic parameters were calculated with assumption that the esterification was the irreversible reaction. The reaction rate constant increasing with temperature. The value of activation energy for esterification of WCO is 42.94 kJ/mol for first order reaction and 35.30 kJ/mol for second order reaction.
ULTRASONIC TREATMENT EFFECT ON THE CONSOLIDATION OF Fe-Cr PARTICLE MIXTURES AFTER COMPACTION AND SINTERING PROCESS Silalahi, Marzuki; Untoro, Pudji; Suharno, Bambang; Harjanto, Sri
Metalurgi Vol 29, No 2 (2014): Metalurgi Vol.29 No.2 Agustus 2014
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (449.765 KB) | DOI: 10.14203/metalurgi.v29i2.289

Abstract

ULTRASONIC TREATMENT EFFECT ON THE CONSOLIDATION OF Fe-Cr PARTICLEMIXTURES AFTER COMPACTION AND SINTERING PROCESS. Fe-Cr microalloys which obtained byultrasonic method are the initial cores for the consolidation process. Therefore its facilitate the formation of thehomogeneous bulk of Fe-Cr alloy with a stable phase. In this research, the synthesis of bulk of Fe-Cr alloy fromthe particles mixture of (Fe+Cr) as the ultrasonic treatment results has been carried out. The particlesconsolidation has been carried out through a process of compaction without adding any lubricants and followedby sintering process in the quartz glass capsules by using induction furnace at 1300 °C. Consolidation of mixtureof Fe-Cr particles that have not undergone previous ultrasonic treatment is also made for a comparison. Theinvestigation by using the SEM (scanning electron microscope)- and density measurements method werepreformed on the Fe-Cr green powders compaction. The bulk of Fe-Cr alloys that are produced trough sinteringprocess was observed using SEM-EDS (energy dispersive spectroscopy), XRD (x-ray diffraction), and densitymeasurements method. The bulk of Fe-Cr alloy prepared with ultrasonically treated Fe-Cr microalloy powders,is more homogeneous in composition and has a better phase stability in comparison to Fe-Cr powders preparedwithout the ultrasonic treatment. Production of bulk Fe-Cr alloy in quartz glass capsule during the sinteringprocess has produced Fe-Cr alloy without oxides.
PENGARUH JENIS PADUAN MIKRO FE-CR HASIL METODE ULTRASONIK PADA PEMBENTUKAN BONGKAH PADUAN FE-CR MELALUI SINTERING DUA TAHAP Silalahi, Marzuki; Untoro, Pudji; Suharno, Bambang; Harjanto, Sri
Jurnal Sains Materi Indonesia Vol 15, No 3: APRIL 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 (1108.741 KB) | DOI: 10.17146/jsmi.2014.15.3.4353

Abstract

PENGARUH JENIS PADUAN MIKRO Fe-Cr HASIL METODE ULTRASONIK PADA PEMBENTUKAN BONGKAH PADUAN Fe-Cr MELALUI SINTERING DUA TAHAP. Fe-Cr adalah paduan yang memiliki ketahanan pada suhu tinggi dan potensial digunakan sebagai interkonek pada sel bakar Solid Oxide Fuel Cell (SOFC). Pada penelitian ini telah dilakukan sintesis bongkah paduan Fe-Cr dengan menggunakan serbuk paduan mikro Fe-Cr hasil sintesis dengan metode ultrasonik. Metode ultrasonik dimanfaatkan untuk sintesis paduan mikro Fe-Cr melalui penggunaan gelombang suara ultrasonik. Langkah yang dilakukan adalah konsolidasi partikel paduan mikro Fe-Cr melalui kompaksi tanpa lubrikan, kemudian dalam kapsul kaca kuarsa dilakukan proses sintering sampai 1000 oC selama 1 jam, lalu dilanjutkan sintering hingga 1300 oC selama 2 jam, lalu didinginkan dalam tungku. Karakterisasi struktur mikro dilakukan dengan Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (SEM-EDS), X-Ray Diffraction (XRD) disertai analisis dengan metode Rietveld dan pengukuran densitas sesungguhnya. Partikel paduan mikro Fe-Cr seutuhnya lebih stabil dan konsisten dalam pembentukan fasa bongkah paduan Fe-Cr melalui sintering bertahap. Diperoleh bongkah paduan Fe-Cr homogen tanpa oksida.