28 research outputs found
X-Ray Diffraction and Microstructure of Tin Dioxide with Addition of Fe
Get PDFPreparation and characterization of tin dioxide, SnO2, had been carried out by precipitation process of SnCl2.2H2O in ammonia and aqua solutions with comparison of 1 : 7. FeCl3 was added to solution with variation of 0, 0,1, 0.2, 0.5 and 1.0 gram respectively and then sintered at 900°C. The X-ray diffraction (XRD) analysis shows that the intensity of diffraction increases with the addition of Fe. The addition of Fe does not cause the new phase. Generally, the Bragg angle is relative same for all samples that means Fe does not change significantly the cell parameters. Scanning electron microscopy (SEM) image shows the microstructure changed with the addition of Fe. On the small addition, the microstructure tends to oval and on the larger addition to plateau
Microstructural design and characterisation of alumina/aluminium titanate composites
No full textA new but relatively simple processing study was conducted to investigate the microstructure-property relationships of alumina/aluminium titanate (AAT) composites. The objectives of this study were: (a) to develop a process for fabricating AAT and β-spodumene modified AAT composites using a solid-state reaction method and functionally-graded AAT using an infiltration technique, and (b) to evaluate the effects of dispersed aluminium titanate (AT) on the phase relations, microstructure and mechanical properties of alumina-based composites. The study has revealed that the processing procedures played an important rule in the microstructural development of AAT composites. The microstructure and properties of AAT composites have been found to be strongly influenced by the presence of dispersed AT. The phase relations in the AAT system have been characterised by x-ray diffraction (XRD) and neutron diffraction (ND). Rietveld analysis showed that the AT content increased in proportion with the amount of rutile added. The dynamic ND study showed that AT commenced to form at ~1310°C The presence of AT caused a reduction of hardness but an improvement in fracture toughness. In addition, the presence of AT hindered the processes or kinetics of sintering and densification. The use of β-spodumene has been investigated as a liquid-phase-sintering aid for the densification of AAT composites. XRD, ND, differential thermal analysis (DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Vickers indentation were used to characterise the effect of β-spodumene on the phase relations, densification, microstructure and mechanical properties of AAT composites. The presence of β-spodumene was found to have a profound influence on the phase relations, densification, microstructure and properties of AAT composites.The addition of β-spodumene caused a small reduction of AT content and a commensurate increase of alumina phase. Functionally-graded AAT composites have been successfully synthesised through infiltration of porous alumina preform with a solution containing TiCl4. The infiltration kinetics of liquid into porous alumina preform has also been investigated and modelled. It was found that the infiltration rate equation proposed by Washburn was proven to be suitable for describing the kinetics of infiltration in terms of preform sintering temperature, viscosity, and multiple infiltrations. The influence of applied pressure was consistent with the model proposed by Travitzky and Shlayen, where the applied pressure enhanced the rate of infiltration. Pre-sintering of alumina preform at 900, 1000 and 1100°C for 2 h resulted in different rates of infiltration which may be attributed to a varying degree in tortuosity of the pore channels. The graded composition character of functionally-graded AAT composites has been determined by XRD and grazing incidence synchrotron diffraction (GISRD). Graded compositions from Rietveld refinement analysis showed that the concentration of AT decreased with depth. In contrast, the α-A12O3 content increased with depth. Microstructural examination by SEM showed that the content of AT grains was the most abundant near the surface and decreased gradually with an increase in depth. The hardness results showed that FGM had a soft graded-region (AT rich) but hard non-graded alumina region.The lower hardness in the graded region can be attributed to the presence of intrinsically soft AT phase. The presence of graded AT caused a considerable improvement in damage tolerance. The isothermal decomposition of AT at 1100°C both in air and vacuum has been studied. Both ex-situ and in-situ studies have been conducted to examine the effect of environment on the decomposition behaviour of AT. The addition of MgO was effective in enhancing the thermal stability of AT against decomposition both in air and in vacuum
Implementation of student’s worksheet based on project based learning (pjbl) to foster student’s creativity
Get PDFThis study aimed to foster student creativity through the use of student worksheet based on Project Base Learning (PjBL) on dynamic electrical material in making alternative power sources. The research method is using a pre-experimental design with One-Shot case study type. The study population was students of class IX MTs Al-Islah in Pesawaran Lampung. A sample of one class consisting of 30 people was obtained by purposive sumpling. Data analysis was done by using descriptive concerning creativity, product, and response of students to see effectiveness of learning. The results showed that the application of student worksheet based on project based learning is overall effective to foster creativity of student. Based on the average of student’s creativity, the result is 80% which categorized as “creative.” Based on the average of student’s product, the result is 76.2% which categorized as “valuable.” The student’s response is positive as much as 92% which categorized as “very agree.
Analisis Termal-hidrolik Reaktor Cepat Berpendingin Gas (Gas Cooled Fast Reactor) Menggunakan Metode Runge Kutta
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Student Worksheet Static Fluid Material Based on Scientific Approach Using Giuded Inquiry Model
No full textThis Research and development goal is to produce Student Worksheet (SWS) static fluid material based on the scientific approach using guided inquiry learning model, which is easy, interesting, useful and effective. This research was conducted through seven stages, namely: pra-research and data collection stage, planning stage, pra-developing product stage, pra-test stage, revising design stage, product test stage, and revising product stage. The pra-study stage consists of a literature study and teacher and student assessment analysis in Al Kautsar Bandar Lampung high school. The developing stage is produces (SWS) static fluid material with scientific approaches based using guided inquiry learning model with well validated of design expert and well enough of the material expert. The product test stage had been held on the sample with random cluster sampling technique which XI.IPA-5 class as the experimental class and XI.IPA-4 class as the control class. The results of this study indicate that the developing result SWS s has the easy category, interesting, useful, and good enough effective with the N-gain 0.599
MODELING INFILTRATION KINETICS OF LIQUIDS INTO POROUS ALUMINA PREFORMS
Get PDFMODELING INFILTRATION KINETICS OF LIQUIDS INTO POROUS ALUMINA PREFORMS. Alpha-alumina preform was infiltrated with different infiltrant and pressure for studying the infiltration kinetic. Effects of pre-sintering temperature, type of infiltrant, pressure and multiple infiltrations on the rate of infiltration into porous alumina preforms were described. The pore radius of alumina preform is calculated based on the preform water system by using Washburn model. The pore radius from this model, r of 0.0147 μm is good agreement to the average pore radius found by using mercury porosity measurement, r of 0.0170 μm. The pore radius of 0.0147 μm is used to calculate the rate of infiltration, k. The k factors are 64.83 x 10-5 ms½ and 27.11 x 10-5 ms½ for water and TiCl3 respectively without involving pressure in the calculation. On the other hand, by using pressure, the k factors are 75.14 x 10-5 ms½ and 31.40 x 10-5 ms½ for water and TiCl3 respectively. Other formulas were also included as comparisons. The kinetic of water and titanium trichloride alumina preform system is parabolic in time or linier in square root of time
Pengaruh Variasi Pelarut antara Amoniak dan Aquades terhadap Karakterisasi Difraksi Sinar-X Bahan SnO2
Get PDFSynthesis has been done and characterization of X-ray diffraction (XRD) SnO2 materials produced by the precipitation process from starting materials with SnCl2 variation between ammonia and solvent aquades each one to one up to six. C for 4 hours Sintering temperature of the sample conducted at 1050. The results of qualitative analysis of the sample shows clearly the presence of SnO2 phase with tetragonal crystal structure and space group P42/MNM. The results of refining the XRD data using SnO2 sample Rietveld method between 1.52 to 4.08 2 produces the best matching score ( In general, all cell parameters length is the same sample. In comparison the variation of solvent 1:4, 1:5 and 1:6 high changes in the hkl diffraction peak (110) and (011) as a result of changes in grain size sample.Keywords: Tin Dioxide (SnO2), Presipitation, Rietveld Analysi
