Effect Of Lanthanum Oxide (La2o3) Addition On The Properties Of Calcium Copper Titanate (CaCu3Ti4O12)
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Date
2010-12
Authors
sharif, Nur Shafiza Afzan
Journal Title
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Publisher
Universiti Sains Malaysia
Abstract
The electroceramic of CaCu3Ti4O12 (CCTO) was prepared by solid state reaction method using three main raw materials of Ca(OH)2, CuO, and TiO2 powders. This study was focused in characterization of CCTO properties which was calcined and sintered through conventional and microwave sintering techniques. La doping method was applied to CCTO with substitution of Ca from 1 to 10 mole %. The starting materials were wet mixed, calcined, formed by pressing, and finally were sintered according the processing flow. The mixed powder was calcined at temperature of 900 ºC for 12 hours using furnace to form the CCTO compound. CCTO pellet were sintered at 1000 ºC for 10 hours using furnace under ambient air and synthesized under argon environment using tube furnace. Then, the samples that have been sintered using furnace were post heated using microwave method for 30 and 60 minutes. Density improved while the porosity decrease at higher dopant concentration. XRD analysis proved the formation of CCTO phase. SEM images shows that grain size becomes smaller for increasing the mole percent of doped material for sample synthesized with and without gas. Dielectric constant show higher value (~ 18000) and dielectric loss give better result (~ 0.3) for samples synthesized under argon environment compared to samples sintered without gas using aluminum electrode. Besides, the experimental results show a significant enhancement in dielectric behavior when using silver electrode. The impedance analysis shows that, the improvement of the dielectric constant mainly results from the decrease in the insulating property of the grain boundary. Moreover, using different electrode as coating material observed that there is no different in impedance response where the result of resistance in grain and grain boundary for both samples evaporated in different electrode were similar to each other. Microwave treatment process is found to be effective where this technique produce better morphology and dielectric properties if compared to untreated samples.
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Keywords
Effect of lanthanum oxide (la2o3) addition , on the properties of calcium copper titanate