Center for Science and Technology of Advanced Materials

BATAN, Indonesia

Center for Science and Technology of Advanced Materials

BATAN, Indonesia
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Indriana K.,Gadjah Mada University | Inna Y.K.,Gadjah Mada University | Chotimah,Gadjah Mada University | Salim M.,Center for Science and Technology of Advanced Materials | And 2 more authors.
Materials Science Forum | Year: 2017

The effect of alkaline solvent of NaOH and NH3 in the synthesis of nanostructured titania (TiO2) has been studied. Powder of anatase titania as the precursor was mixed with various volume ratios of 10 M of NaOH and 15 M of NH3. The mixture was heated in Teflon-lined autoclave at 150 °C for 24 h. The as-synthesized TiO2 powders were then washed with 0.1 M HCl and calcined at 300 °C. The calcined samples were characterized using TEM (transmission electron microscope), and XRD (X-Ray diffraction). Raman spectroscopy was further used to determine the contributing crystalline phases for the synthesized TiO2. It is shown that varying the solvent ratios of NOH to NH3 resulted in nanotubes, nanosheets, and nanoparticle morphology of TiO2. The TEM images showed the formation of nanotube structure in alkaline ratio NaOH:NH3 of 1:0 and 3:1, with diameter of about 10 nm. At volume ratio of 1:1, the nanosheets and nanotubes both were formed and at volume ratio of NaOH:NH3 of 1:3, nanosheets contributed as its main morphology. While, at fully NH3 solvent, the nanospheres with anatase domain were produced. Raman spectra confirmed that the major contributor for hydrothermal synthesis employing less NaOH for volume ratio of NaOH:NH3 of 3:1 was predominantly anatase with slight presence of titanate. For volume ratio at higher NH3 the presence of titanate is not prominent, but the morphology has already changed into more nanosheet and then nanospheres. The crystallinity of TiO2 anatase crystalline phase was enhanced as more NH3 utilized. © 2017 Trans Tech Publications, Switzerland.


Gunanto Y.E.,Pelita Harapan University | Jobiliong E.,Pelita Harapan University | Adi W.A.,Center for Science and Technology of Advanced Materials
AIP Conference Proceedings | Year: 2016

Single phase of nanocrystalline BaxSr1-xFe12O19 (x = 1.0; 0.6; and 0.4) was successfully synthesized by mechanical milling method and thermal process. Stoichiometric quantities of analytical-grade SrCO3, BaCO3, and Fe2O3, were mixed and milled using a high-energy milling. The mixture of all precursors was sintered at a temperature of 1000 °C for 10 hours. The refinement of x-ray diffraction trace for all samples confirmed a single phase material with a hexagonal structure. The increase of the amount of strontium content in the barium atoms in the BaxSr1-xFe12O19 system can decrease the lattice parameter which have been successfully substituted into the barium atoms. The calculation result of cationic distribution showed that the BaxSr1-xFe12O19 (x = 0.6) and (x = 0.4) samples have nominal composition of Ba0,61Sr0,39Fe12O19 and Ba0,37Sr0,63Fe12O19, respectively. Results of the mean of crystallite size evaluation for respective powder materials showed that the BaxSr1-xFe12O19 (x = 1.0; 0.6; and 0.4) samples have the crystallite size of 22nm, 25nm and 34nm, respectively. We concluded that the cationic distribution of barium atoms was successfully substituted by strontium atoms approaching the nominal stoichiometric composition. © 2016 AIP Publishing LLC.


Gunanto Y.E.,Pelita Harapan University | Cahyadi L.,Pelita Harapan University | Adi W.A.,Center for Science and Technology of Advanced Materials
AIP Conference Proceedings | Year: 2016

The synthesis and characterization of composition Ba0.6Sr0.4Fe11-zMnTizO19 (z = 0; 1; 2 and 3) compound by solid state reaction using mechanical milling have been performed. The raw materials were BaCO3, SrCO3, Fe2O3, MnCO3, and TiO2. The mixed powder was compacted and sintered at 1000°C for 5 hours. X-ray diffraction studies indicate expansion of hexagonal unit cell and compression of atomic density with substitution of Mn2+ and Ti4+ ions. Effect of substitution upon magnetic properties revealed that total magnetization, remanence, and coercivity changed with substitution due to preferential site occupancy of substituted Mn2+ and Ti4+ ions. Since the coercivity and total magnetization may be controlled by substitution while maintaining resistive properties, this material is useful for microwave absorber. © 2016 Author(s).


Gunanto Y.E.,Pelita Harapan University | Adi W.A.,Center for Science and Technology of Advanced Materials | Steven E.,CNRS French National High Magnetic Field Laboratory | Kurniawan B.,University of Indonesia | And 2 more authors.
IOP Conference Series: Materials Science and Engineering | Year: 2017

We have successfully measured physical and magnetic properties of the La0.5Ca0.5Mn0.9Cu0.1O3 at temperature in the range of 10-100 K. Physical properties have covered electrical resistivity and specific heat. The properties, which serve as a function of temperature, were investigated by using Physics Properties Measurement System (PPMS) with and without an external magnetic field up to 8.5 Tesla. The magnetic structure was characterized using High-Resolution Powder Diffraction (HRPD) at room and low temperatures. Furthermore, the magnetization was measured by using Magnetic Properties Measurement System (MPMS) with the external magnetic field of 0-7 Tesla. In the temperature interval of 10-53 K, the resistivity of the sample increased with the increasing of external magnetic field. At temperatures T < 53 K, the samples were crystalline metal. This was revealed by fitting the graph Ln R as a function of 1/T. At temperatures T > 53 K, the sample was an insulator according to fittings Ln R as a function of 1/T 0.25. The result was also shown by the decreasing value of the resistivity of the sample. The transition temperature of the metal-insulator (TMI ) decreased with the increasing of external magnetic field, i.e. from 60 K without an external magnetic field to 53 K with external magnetic field 8.5 Tesla. A coefficient electron specific heat and specific heat of spin wave increased, and phonon specific heat was relatively unchanged in the presence of an external magnetic field. Results of HRPD experiment were analyzed by using Fullprof program. At room temperature, the sample had the paramagnetic phase, while at low temperatures of 20 K it had antiferromagnetic phase. Temperature phase transition from the paramagnetic to antiferromagnetic phase or Neel temperature was around 225 K. However, the saturation magnetization of the sample was not observed. © Published under licence by IOP Publishing Ltd.


Sarwanto Y.,Center for Science and Technology of Advanced Materials | Adi W.A.,Center for Science and Technology of Advanced Materials
IOP Conference Series: Materials Science and Engineering | Year: 2017

Modification of pseudobrookite Fe2-xMnxTiO5 with solid state reaction method using a mechanical milling has been synthesized. Raw materials used to prepare these samples were Fe2O3, MnCO3, and TiO2. Fe2O3 and TiO2 powders (ratio of 1:1) were mixed with MnCO3 powder at various composition of x = 0; 0.1; 0.2; 0.3; 0.4; 0.5; and 1, which each composition was added with 50 ml ethanol and then milled for 5 hours through high energy milling, after that sintered at 1000 °C for 5 hours by using box furnace. The phases of Fe2-xMnxTiO5 were measured by using X-ray diffraction (XRD) and then identified by using Match program. The crystal structure was analyzed by using the program of General Structure Analysis System (GSAS). Quality fitting of Rwp and χ2 (chi-squared) are relatively good because based on the curve of normalized error distribution looks just left background and its normal probability plot shows the value of comparable between observation and expectation. The refinement analyses of X-ray diffraction patterns showed that the samples formed single phase for x ≤ 0.3. However, the samples of x > 0.3 were multi-phases. The single phase of sample had composition of pseudobrookite Fe2TiO5 with orthorhombic structure, space group of C m c m (63), the lattice parameters of a = 3.7390 Å, b = 9.7790 Å, and c = 9.9780 Å, α = β = γ = 90°, V = 364.83 Å3, and ρ = 4.360 g.cm-3. Meanwhile, the other phase analysis for the composition of x > 0.3 is bixbyite (FeMnO3). The bixbyite has a cubic structure, under the space group of I a - 3 (206), the lattice parameters of a = b = c = 9.40 Å, α = β = γ = 90°, V = 830.58 Å3, and ρ = 5.078 g.cm-3. © Published under licence by IOP Publishing Ltd.


Rivai A.K.,Center for Science and Technology of Advanced Materials | Dimyati A.,Center for Science and Technology of Advanced Materials | Adi W.A.,Center for Science and Technology of Advanced Materials
IOP Conference Series: Materials Science and Engineering | Year: 2017

One of the advanced materials for application at high temperatures which is aggressively developed in the world is ODS (Oxide Dispersion strengthened) steel. ODS ferritic steels are one of the candidate materials for future nuclear reactors in the world (Generation IV reactors) because it is able to be used in the reactor above 600 °C. ODS ferritic steels have also been developed for the interconnect material of SOFC (Solid Oxide Fuel Cell) which will be exposed to about 800 °C of temperature. The steel is strengthened by dispersing homogeneously of oxide particles (ceramic) in nano-meter sized in the matrix of the steel. Synthesis of a ferritic ODS steel by dispersion of nano-particles of yttrium oxide (yttria: Y2O3) as the dispersion particles, and containing high-chromium i.e. 14% has been conducted. Synthesis of the ODS steels was done mechanically (mechanosynthesis) using HEM (High Energy ball Milling) technique for 40 and 100 hours. The resulted samples were characterized using SEM-EDS (Scanning Electron Microscope-Energy Dispersive Spectroscope), and XRD (X-ray diffraction) to analyze the microstructure characteristics. The results showed that the crystal grains of the sample with 100 hours milling time was much smaller than the sample with 40 hours milling time, and some amount of alloy was formed during the milling process even for 40 hours milling time. Furthermore, the structure analysis revealed that some amount of iron atom substituted by a slight amount of chromium atom as a solid solution. The quantitative analysis showed that the phase mostly consisted of FeCr solid-solution with the structure was BCC (body-centered cubic). © Published under licence by IOP Publishing Ltd.


Adi W.A.,Center for Science and Technology of Advanced Materials | Wardiyati S.,Center for Science and Technology of Advanced Materials | Dewi S.H.,Center for Science and Technology of Advanced Materials
IOP Conference Series: Materials Science and Engineering | Year: 2017

Synthesis and characterization of La2O3 nanoneedles have been successfully carried out by using hydrolysis reaction with NH4OH as a solvent. La2O3 was prepared from LaCl3 solution. LaCl3 was preheated on a hotplate and stirred by using a magnetic stirrer, then added solution of NH4OH 1 M with the variation speed drops of 3 ml, 6 ml and 9 ml to obtain white precipitation La(OH)3 until a pH of 9. Stirring was continued until 1 hour. A white precipitate formed is separated from the effluent by centrifugation method with 3000 rpm and neutral pH. Then, the precipitate was dried in an oven at a temperature of 70 °C and sintered at 1000 °C to get La2O3 nanoneedles. The identification of sample phase was carried out by using X-ray diffractometer (XRD). The refinement results of X-ray diffraction pattern shows that the samples have a single phase of La2O3. The morphology of the nanoneedles was observed by using the transmission electron microscope (TEM). Meanwhile, the reflection and transmission of electromagnetic wave were measured by using the vector network analyzer (VNA) at X-band frequency. © Published under licence by IOP Publishing Ltd.


Adi W.A.,Center for Science and Technology of Advanced Materials | Indro M.N.,Bogor Agricultural University | Kusumastuti A.A.,Bogor Agricultural University
IOP Conference Series: Earth and Environmental Science | Year: 2017

We have carried out modification of La0.8Ba0.2MnxFe1/2(1-x)Ti1/2(1-x)O3 (x = 0.1 - 0.8) magnetic materials by wet milling method. Raw materials of La2O3, BaCO3, Fe2O3, TiO2 and MnCO3 were mixed according to stoichiometry calculation for each composition. The mixture was milled for 5 hours and then sintered at 1000 °C for 5 hours. The refinement results by X-ray diffraction pattern shows that the increasing Mn composition enhances the mass fraction of La0.8Ba0.2MnxFe1/2(1-x)Ti1/2(1-x)O3 phase which has the same structure as LaMnO3. For x = 0.8 a single phase of LaMnO3 was formed. The single phase has a crystal monoclinic crystal structure with space group of I 1 2 / a 1, with lattice parameters given by a = 5.519(5) Å, b = 5.5537(5) Å and c = 7.8176(9) Å, α = γ = 90o and β = 90.345(6)o, V = 239.64(3) Å3, ρ = 6.463 gr.cm-3, wRp = 5.96, and χ2 (chi-squared) = 1.17. The hysteresis curve shows that the sample with composition x = 0.8 produces ferromagnetic behaviour at room temperature. The ferromagnetic properties arise due to the mixed valence of Mn3+ and Mn4+ ions through a double exchange mechanism. The results of the microwave absorption indicated that there was a broadening of absorption peak frequency at 9.9 GHz. The reflection loss (RL) increases with the increasing of LaMnO3 phase. For x = 0.8 we have the best of RL where the microwave absorption was calculated reaching 95% at the highest peak frequency with a thickness of 1.5 mm. Thus we have been successful in creating a single phase of La0.8Ba0.2MnxFe1/2(1-x)Ti1/2(1-x)O3 with application as a microwave absorber. © Published under licence by IOP Publishing Ltd.


Rivai A.K.,Center for Science and Technology of Advanced Materials | Shabrina N.,FTMD | Setiawan A.R.,FTMD
Journal of Physics: Conference Series | Year: 2017

Synthesis and characterization of 8YSZ (8%mol Y2O3 - ZrO2) and 5GDC (5%mol Gd2O3-CeO2) combination in the form of composite and dissimilar bulk using sonochemistry assisted sol-gel method have been done. 8YSZ and 5GDC powders were produced from sol-gel route method. Each of the powder was then ultrasonicated for 30 hours with 25kHz±50Hz of frequency and 39% of amplitude. Toluene was used as a solution for the ultrasonication process. 8YSZ/5GDC composite was made by mixing the powders of 50%:50% in weight, and afterward compacted become a pellet. 8YSZ/5GDC dissimilar bulk was made by connected between 8YSZ pellet and 5GDC pellet at a flat part, and afterward re-compacted become a single pellet. Then, the pellets were sintered at 1400°C of temperature for 3 hours. The results showed that the ionic conductivity of the composite is higher than the dissimilar bulk. © Published under licence by IOP Publishing Ltd.


Erizal,Center for Application of Isotopes and Radiation | Abbas B.,Center for Application of Isotopes and Radiation | Sukaryo S.G.,Center for Science and Technology of Advanced Materials | Barleany D.R.,Sultan Ageng Tirtayasa University
Indonesian Journal of Chemistry | Year: 2015

A series of superabsorbent hydrogels were synthesized from partially neutralized acrylic acid with varying degree of neutralization (0-1) using gamma radiation. The effects of degree neutralization of acrylic acid on swelling ratio were studied. DSC measurement was performed to understand the type of end products resulting from irradiation. The morphologies of the hydrogels were examined using SEM. The chemical changes of the hydrogels were characterized using FTIR. At optimum conditions (10 kGy, 15 min), the hydrogels with neutralization degree 0.5 exhibited rapid swelling with the highest swelling ratio ~1000 g/g. The results of DSC studies confirmed the possible formation of the type hydrogels from irradiated partially neutralized acrylic acid, and the hydrogels showed large numbers of pores from SEM examination. © 2015, Gadjah Mada University. All rights reserved.

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