25 research outputs found
Doping Calcia and Yttria into Zirconia Obtained from by Product of Tin Concentrator to Improve its Ionic Conductivity
No full textZirconia has been prepared from Zircon concentrate by caustic fusion
methods. Zircon is a by product from tin ore concentration plant at Bangka
island of Indonesia. Yttria Stabilized-Zirconia (YSZ) was prepared by
introducing the 8 % mol yttrium oxide into zirconia and sintered at 1500 �C for
5 hours. In order to obtain constant oxygen vacancy of 8 % mol in Zirconia, an
appropriate amount of Yttria and Calcia were introduced into Zirconia and the
mixtures were heated at 1350 oC for 5 hours. Elemental composition was
determined by SEM/EDX and XRF and lattice parameters were determined
using X-ray diffraction method. Ionic conductivity was measured by complex
impedance spectroscopy. The results show that doping of Yttria into Zirconia
(YSZ) and Calcia-Yttria into Zirconia (CYZ) allows phase transformation of
Zirconia from tetragonal with space group P42/nmc into cubic Fm3m and
enhance the ionic conductivity. However, the prepared materials are porous and
have not met the requirement for the electrolyte material yet.
Keywords: electrolyte material; CYZ; SOFC; YSZ; zircon
UTILISATION OF SLAG POWDER FOR CEMENT SUBSTITUTION BASED ON THE COMPRESSIVE STRENGTH AND PENETRATION OF CHLORIDE IONS
No full textUTILIZATION OF SLAG POWDER FOR CEMENT SUBSTITUTION BASED ON THE COMPRESSIVE STRENGTH AND PENETRATION OF CHLORIDE IONS. The availability of waste from nickel ore smelting in the form of slag has increased, this is due to the high nickel production to meet the increasing needs for development and for compound- ing materials for construction materials. This research aims to make a paste from the mixture of Nickel Pig Iron (NPI) slag from PT Indoferro which is used as a substitute for making cement paste. The materials used in this study are cement, nickel slag, water, and zeolite. The cement paste is made with a dimension of 10 cm x 5 cm with each slag used as an amplifier on the paste with a volume variation of 15%, 30%, 45%, and 60%. Each material is weighed according to mix design then mixing the materials, after they are homogeneous, they are put into the mold and then let stand for 24 hours until the paste solidifies and hardens, after 24 hours, the paste sample is removed from the mold and treated at room temperature, after the life is qualified, the paste sample is tested. Results of the compression test show that variations of slag addition to the paste mixture giving maximum compressive strength is the 15% variant for NPI slag. The increase in compressive strength of the slag mixture paste may occur because slag contains cement compounds which can chemically react with Calcium Hydroxide (CH) com- pounds as a result of the hydration reaction of cement with water to form a Calcium Silicate Hydrate (CSH) compound from the hydration result between water and cement to increase adhesion and compressive strength on cement paste
KARAKTERISTIK FISIK DAN KONDUKTIVITAS SPESIFIK BATAS BUTIR DARI ELEKTROLIT PADAT GADOLINIUM CERIA UNTUK APLIKASI INTERMEDIATE TEMPERATURE SOLID OXIDE FUEL CELL
No full textTEKSTUR DEFORMASI DAN REKRISTALISASI BAJA LEMBARAN CANAI DINGIN BEBAS INTERSTISI
No full textTEKSTUR DEFORMASI DAN REKRISTALISASI BAJA LEMBARAN CANAI DINGIN BEBAS INTERSTISI. Perkembangan tekstur kristalografi dipelajari pada baja lembaran bebas interstisi canai dingin. Tekstur yang diamati adalah tekstur deformasi setelah pencanaian dingin dan tekstur rekristalisasi atau tekstur annealing setelah proses annealing. Tekstur deformasi baja lembaran bebas interstisi dipelajarimelalui variasi persen reduksi ketebalan dengan selang reduksi antara 50,5% hingga 90 %. Sementara tekstur rekristalisasi dipelajari melalui variasi laju pemanasan annealing antara 32 oC/jam hingga 128 oC/jam, variasi waktu penahanan annealing antara 5 jam hingga 20 jam dan variasi suhu annealing dari 700 oC hingga 900 oC. Perkembangan tekstur deformasi dan rekristalisasi dipelajari melalui pengujian difraksi sinar-X. Tekstur kristalografi diukur untuk tekstur yang mempengaruhi sifat mampu bentuk, yaitu tekstur [111] dan tekstur [100]. Pengujian tarik terhadap spesimen pada orientasi yang berbeda terhadap arah pencanaian kemudian dilakukan untuk memperoleh nilai r yang merupakan parameter sifat mampu bentuk baja lembaran
SINTESIS DAN KARAKTERISASI FERIT GELOMBANG MIKRO YIG DISUBSTITUSIKAN DENGAN ION Al, Gd
No full textSINTESIS DAN KARAKTERISASI FERIT GELOMBANG MIKRO YIG DISUBSTITUSIKAN DENGAN ION Al, Gd. Telah disintesis ferit untuk kompunen gelombang mikro dari bahan garnet (YIG) yang disubstitusikan dengan Al dan Gd, permeabilitas dan polarisasi magnet berubah dengan penambahan kadar ion Al3+. Pengujian XRD dilakukan untuk menentukan hasil proses proses sintering pada berbagai suhu. Untuk beberapa cuplikan diuji sifat magnetnya dan juga sifat kinerja pada daerah microware dengan dibentuk sirkurator lengkap yang memberikan data parameter, isolasi insertion-loss, diuji dengan Circuit Analyzer gelombang micro (1-8 Ghz). Insertion loss pada umumnya masih terlalu besar karena porositasnya masih terlalu tinggi, jadi perlu perbaikan dalam proses sintesanya
Doping Calcia and Yttria into Zirconia Obtained from by Product of Tin Concentrator to Improve its Ionic Conductivity
No full textCHARACTERISTICS OF ZrO2 ADDED-MgAl2O4 CERAMICS FOR MATRIX OF INERT MATRIX NUCLEAR FUEL (IMF)
No full textCHARACTERISTICS OF ZrO2 ADDED-MgAl2O4 CERAMICS FOR MATRIX OF INERTMATRIX NUCLEAR FUEL (IMF). Some ZrO2 added-MgAl2O4 ceramics for inert matrix of inertmatrix nuclear fuel (IMF) had been fabricated from powders prepared using precipitationmethod. Effect of ZrO2 addition on crystal structure, microstructure and mechanical properties ofthe ZrO2 added-MgAl2O4 ceramics was studied. The ceramics were prepared by mixing ZrO2,MgO and Al2O3 followed by pressing and sintering. The concentrations of ZrO2 additive were 0,5, 10 and 15 mole %. The mixed powder was pressed into green pellets with pressure of4 ton/cm2. The green pellets were sintered at 1600 oC for 2 hours in air. The sintered pelletswere evaluated visually. For microstructure examination, the fractured samples were examinedusing a scanning electron microscope (SEM). Crystal structure of the samples was analyzedusing x-ray diffraction (XRD). Hardness and fracture toughness of the sintered pellets weredetermined using microindentation method with aid of a Vickers microhardness tester fromZwick. It was known that the sintered pellets were visually good. The XRD data showed that theceramics crystallized in spinel cubic with second phase of ZrO2.. The hardness and fracturetoughness of the ceramics increased with the increase of ZrO2 concentration
Electrical Properties of Various Composition of Yttrium Doped-Zirconia Prepared from Local Zircon Sand
No full textDoping
yttrium ions, Y3+ into ZrO2 produced Yttria-Stabilized
Zirconia, YSZ. Various amount of yttrium ions could provide different ionic conductivity. This research investigated
electrical conductivity of various YSZ composition, i.e., 4.5; 8.0 and 10% mol yttrium in ZrO2. The ZrO2
powder used was synthesized from zircon sand, a side product of tin mining
plant, Bangka Island, Indonesia. Structural investigation on the prepared YSZ
found that yttrium ion doping has changed the crystal structure of ZrO2
from monoclinic to cubic, even though the
monoclinic and tetragonal are also still exist.
The Y3+ doping changed the cell parameter of ZrO2
crystal. It indicates that the Y3+ entered into the ZrO2
structure and produced vacancy sites. The highest ionic conductivity is
provided by 8% mol Yttrium doping or
8YSZ, i.e., 2.74×10-4 S.cm-1
at 700oC with an activation energy
of 0.741 eV
Double steps leaching and filtration in caustic fusion method to produce zirconia from local zircon concentrate
No full text
