scholarly journals Konduktivitas Apatit Lantanum Silikat La9.33Si6O26 Hasil Sintesis Hidrotermal dengan Mineraliser NaOH dan KOH

2018 ◽  
Vol 14 (1) ◽  
pp. 1
Author(s):  
Atiek Rostika Noviyanti ◽  
Dani Gustaman Syarif ◽  
Riansyah Amynurdin ◽  
Iwan Hastiawan ◽  
Iman Rahayu ◽  
...  

<p>Apatit lantanum silikat banyak digunakan sebagai elektrolit pada sel bahan bakar padatan (SOFC). Beberapa oksida apatit lantanum silikat La<sub>9.33</sub>Si<sub>6</sub>O<sub>26 </sub>telah disintesis dengan metode hidrotermal guna mengamati pentingnya peranan mineraliser terhadap karakternya. Penelitian ini bertujuan untuk mengetahui pengaruh jenis dan konsentrasi mineraliser terhadap kristalinitas, ukuran partikel dan hubungannya dengan sifat konduktivitas oksida apatit lantanum silikat. Struktur, ukuran partikel dan konduktivitas oksida apatit masing-masing dikarakterisasi dengan XRD, PSA dan spektroskopi impedansi. Oksida apatit lantanum silikat diperoleh dengan melarutkan La<sub>2</sub>O<sub>3</sub> dan Na<sub>2</sub>SiO<sub>3</sub> dengan mol ratio 1,555 menggunakan mineraliser NaOH (3-5 M) dan KOH (0,3-0,7 M). Hasil penelitian menunjukkan bahwa kinerja elektrolit sangat ditentukan oleh kristalinitas dan morfologi apatit lanthanum silikat yang dipengaruhi oleh jenis dan konsentrasi mineralizer. Ukuran apatit lantanum silikat terkecil diperoleh dari hasil sintesis dengan menggunakan mineraliser NaOH 3 M yaitu 1,7889 µm, dengan nilai konduktivitas tertinggi yaitu 1,99×10<sup>-6 </sup>S/cm pada suhu operasi 600 ºC. Berdasarkan hasil tersebut NaOH 3 M merupakan mineraliser yang paling baik untuk menghasilkan apatit lanthanum silikat La<sub>9.33</sub>Si<sub>6</sub>O<sub>26</sub>.</p><p><strong>Conductivity of </strong><strong>L</strong><strong>anthanum </strong><strong>S</strong><strong>ilicate </strong><strong>A</strong><strong>patite </strong><strong>P</strong><strong>hase of La<sub>9.33</sub>Si<sub>6</sub>O<sub>26</sub> </strong><strong>P</strong><strong>repare</strong><strong>d</strong><strong> by </strong><strong>H</strong><strong>ydrothermal </strong><strong>S</strong><strong>ynthesis using NaOH and KOH as </strong><strong>M</strong><strong>ineralizer</strong><strong>. </strong>Lanthanum silicates are used as electrolytes in solid oxide fuel cells (SOFC). Some oxide-based apatite has been synthesized by hydrothermal method to observe mineralizer effect on the process of crystallization. The effect of type and amount of mineralizers for preparing apatite –type lanthanum silicate of La<sub>9.33</sub>Si<sub>6</sub>O<sub>26 </sub>was investigatedon its crystallinity, particle size, as well as on the conductivity properties relationship were investigated. The structure, particle size and conductivity of La<sub>9.33</sub>Si<sub>6</sub>O<sub>26</sub> was characterized using X-ray diffraction, particle size analyzer and impedance spectroscopy respectively. The results show that the electrolyte performance is strongly dependent on the crystallinity and the morphology textural of lanthanum silicate apatite affected by the type and amount of mineralizer. The lanthanum silicate apatiteprepared by La<sub>2</sub>O<sub>3</sub> and Na<sub>2</sub>SiO<sub>3</sub> (molar ratio of La<sub>2</sub>O<sub>3</sub> and Na<sub>2</sub>SiO<sub>3</sub> = 1.555), and NaOH (3; 4; 5 M) and KOH (0,3-0,7 M) as mineralizer. As a result, apatite-type lanthanum silicate was prepare using NaOH 3 M shows smallest particle (1.7889 μm) and highest conductivity (1.99 × 10-6 S / cm at 600 ºC). With respect to both particle size and conductivity, the NaOH 3 M can be selected as a suitable type and amount mineralizer for the preparation of excellent lanthanum silicate apatite La<sub>9.33</sub>Si<sub>6</sub>O<sub>26</sub>. </p>

2015 ◽  
Vol 1112 ◽  
pp. 489-492
Author(s):  
Ali Mufid ◽  
M. Zainuri

This research aims to form particles of hematite (α-Fe2O3) with a basis of mineral iron ore Fe3O4 from Tanah Laut. Magnetite Fe3O4 was synthesized using co-precipitation method. Further characterization using X-ray fluorescence (XRF) to obtain the percentage of the elements, obtained an iron content of 98.51%. Then characterized using thermo-gravimetric analysis and differential scanning calorimetry (TGA-DSC) to determine the calcination temperature, that at a temperature of 445 °C mass decreased by 0.369% due to increase in temperature. Further Characterization of X-ray diffraction (XRD) to determine the phases formed at the calcination temperature variation of 400 °C, 445 °C, 500 °C and 600 °C with a holding time of 5 hours to form a single phase α-Fe2O3 hematite. Testing with a particle size analyzer (PSA) to determine the particle size distribution, where test results indicate that the α-Fe2O3 phase of each having a particle size of 269.7 nm, 332.2 nm, 357.9 nm, 412.2 nm. The best quantity is shown at a temperature of 500 °C to form the hematite phase. This result is used as the calcination procedure to obtain a source of Fe ions in the manufacture of Lithium Ferro Phosphate.


2014 ◽  
Vol 906 ◽  
pp. 18-24 ◽  
Author(s):  
Bao Lin Zhang ◽  
Bin Bin Zhang ◽  
Ning Ning Wang ◽  
Jing Ming Fei

The effect of milling time and sintering process on the dielectric properties of BaTiO3-based X9R ceramics was investigated. The characterization of the raw powders and the sintered ceramic was carried out by X-ray diffraction and scanning electron microscopy. The particle size distribution of the mixed powders was examined by Laser Particle Size Analyzer. The results shown that with the milling time extended, the Cruie Peak was depressed, or even disappeared. Moreover, with the rise of sintering temperature, the dielectric constant of the ceramics increased and the dielectric loss decreased gradually. Eventually, by milling for 11h and sintering at 1090°Cfor 2h, good dielectric properties were obtained, which were ε25°C≥ 2526, εr/εr25°C≤± 12% (–55~200°C), tanδ≤1.12% (25°C).


2018 ◽  
Vol 281 ◽  
pp. 859-864
Author(s):  
Yan Xing ◽  
Meng Fei Zhang ◽  
Tian Jun Li ◽  
Wei Pan

La2NiO4+σ nanofibers exhibiting typical Ruddlesden–Popper structure (K2NiO4) were fabricated by a facile electrospinning method. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to analyze the structure, morphology and crystal process of the La2NiO4+σ nanofibers. For electrical properties measurement, uniaxially aligned nanofibers were directly collected and assembled into electrode. In our research, La2NiO4+σ phase forms above 873K with no impurity phase emerges during the thermal treatments. The nanofibers are smooth and uniform throughout the entire length and the grain is growing as calcination temperature increases. Furthmore, the La2NiO4+σ nanofibers own high mixed conductivity at 773K, laying good foundation for intermediate temperature solid oxide fuel cells application.


2018 ◽  
Vol 34 (6) ◽  
pp. 3088-3094 ◽  
Author(s):  
Abdul Wahid Wahab ◽  
Abdul Karim ◽  
Nursiah La Nafie ◽  
Nurafni Nurafni ◽  
I. Wayan Sutapa

Silver nanoparticles have been synthesized by reduction method using extract of Muntingia calabura L. leaf a bioreductor. The process of silver nanoparticles formation was monitored by UV-Vis method. The results showed that the absorbance values increased according to the increase of reaction time. Maximum absorption of silver nanoparticle was obtained at a wavelength of 41-421 nm. The size of silver nanoparticles was determined using a PSA (Particle Size Analyzer) with a particle size distribution of 97.04 nm. The functional groups compound that contribute in the synthesis was analyzed using Fourier Transform Infrared Spectroscopy (FTIR). Morphology of the silver nanoparticles was observed by an Scanning Electron Microscope instrument and the structure characterization of the compounds were analyzed using X-Ray Diffraction. The glucose nanosensor based on silver nanoparticles have the measurement range of 1 mM - 4 mM with the regretion (R2) is 0,9516, the detection limit of sensor is 3,2595 mM, the sensitivity of sensor is 2,0794 A. mM-1. mM-2.


2012 ◽  
Vol 727-728 ◽  
pp. 657-662
Author(s):  
Reinaldo Azevedo Vargas ◽  
Everton Bonturim ◽  
Marco Andreoli ◽  
Rubens Chiba ◽  
Emília Satoshi Miyamaru Seo

The (La0.60Sr0.40)(Co0.20Fe0.80)O3-δ - LSCF, (Ce0.90Gd0.10)O1.95 - CGO composites and LSCF were deposited by wet powder spraying deposition method for the purpose of investigating their potential use in Intermediate Temperature Solid Oxide Fuel Cells. The interlayers are necessary between CGO electrolytes and LSCF cathodes in order to improve the performance of these materials. LSCF particles synthesized by citrate technique were calcined at 900 °C for 4 h and, their LSCF-CGO composites and LSCF suspensions deposited on CGO substrate and, sintered in 1100 °C for 1 h, were formed pseudo-perovskite. The ceramics materials were analyzed by X-ray diffraction (XRD) and chemical composition of different half-cells layers by scanning electron microscope with energy dispersive (SEM-EDS). The results are in agreement with the literature and indicate that route studied is adequate for crystal structures formation compatible with films the 35 µm thick total for study of conductivity between the cathode and the electrolyte.


2010 ◽  
Vol 93-94 ◽  
pp. 566-569
Author(s):  
Wassayamon Singkha ◽  
Sutin Kuharuangrong

La3Ni2O7±δ and La2.9Sr0.1Ni2O7±δ Ruddlesden-Popper nickelate were synthesized via citrate gel method. The electrical property of Mn and Co dopants on Ni site in these systems was investigated as possible cathode for solid oxide fuel cells. The result of X-ray diffraction shows the presence of La2NiO4 in La3Ni2-xMxO7±δ and La2.9Sr0.1Ni2-xMxO7±δ (M = Mn or Co) as M content increases from x = 0.1 for Mn and x = 0.2 for Co. With further increase of Mn dopant (x ≥ 0.4), LaMnO3 and La2O3 appear with La2NiO4. The grain size of sintered sample decreases as Mn content increases. However, it slightly decreases with increasing Co content. The TEC value increases with Co content. The DC four-point measurement shows a decrease in the conductivity as Co content increases for both La3Ni2-xCoxO7±δ and La2.9Sr0.1Ni2-xCoxO7±δ systems.


2014 ◽  
Vol 34 (2) ◽  
pp. 373-379 ◽  
Author(s):  
Hideki Yoshioka ◽  
Hiroyuki Mieda ◽  
Takahiro Funahashi ◽  
Atsushi Mineshige ◽  
Tetsuo Yazawa ◽  
...  

1999 ◽  
Vol 14 (3) ◽  
pp. 906-911 ◽  
Author(s):  
S. K. Bhaumik ◽  
C. Divakar ◽  
S. Usha Devi ◽  
A. K. Singh

Starting from elemental powders, simultaneous synthesis and compaction of SiC were conducted at 3 GPa pressure and temperatures in the range 2100–2900 K. The sintered compacts were characterized by x-ray diffraction, microhardness measurements, and microscopic studies. The efficiency of formation of SiC was dependent on the particle size of the silicon powder, crystallinity of the reactant carbon, molar ratio of silicon and carbon, and synthesis temperature and time. Carbon in excess of the stoichiometric amount was required to obtain compacts free from residual silicon. The SiC samples, with a Si: C molar ratio 1: 1.05, prepared at 2100 K for 300 s had a density and hardness of 3.21 g/cm3 (98.8% of theoretical density) and 22 GPa, respectively. The crystal structure of the SiC depended on the synthesis temperature. Pure β–SiC in the temperature range 2100–2500 K, and a mixture of α– and β–SiC above 2500 K were obtained. The β–SiC was highly crystalline and nearly defect-free.


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