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Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃

Master of Science in Materials Engineering

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Bibliographic Details
Main Author: Najwa Shafiqa, Anwar
Other Authors: Mohd Sobri, Idris, Dr.
Format: Thesis
Language:English
Published: Universiti Malaysia Perlis (UniMAP) 2016
Subjects:
Fuel cells
Transparent ceramics
LaYO₃
Solid electrolyte
Polycrystalline ceramics
Online Access:http://dspace.unimap.edu.my:80/xmlui/handle/123456789/77862
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spelling my.unimap-778622023-02-16T08:09:28Z Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃ Najwa Shafiqa, Anwar Mohd Sobri, Idris, Dr. Fuel cells Transparent ceramics LaYO₃ Solid electrolyte Polycrystalline ceramics Master of Science in Materials Engineering LaYO₃ is a polycrystalline ceramic with the perovskite type oxide structure. LaYO₃ was prepared using solid state synthesis method. Initially, the sample was heated between 1200 °C to 1500 °C for 10 hours and slowly cooled in air. The existence of secondary phases that belongs to orthorhombic shows the polymorphism properties of LaYO₃. Pure phase monoclinic structure was successfully synthesized after heated at 1500 °C for 10 hours and rapidly cooled in liquid nitrogen. Then, the pure monoclinic LaYO₃ powder was pelletized using cold isostatic pressing and been fabricated by two-step sintering method. For the first-step sintering (T1), pellets were heated at 1300 °C for 1 minute and then quenched into liquid nitrogen. The pellets were then reheated at the relatively lower temperature between 1000 °C to 1250 °C and denoted as T2 for 15 hours holding time. By increasing T2, the relative density increased from ~87 % to ~95 %. Percentage of shrinkage also linearly increased within error. Microstructural analysis shows homogenous microstructure. The grain size was directly proportional to the relative density. Cole-cole plot from complex impedance of sintered LaYO₃ shows one semicircle contribute to the bulk phenomenon responsible. The conductivity for samples sintered between 1000 °C to 1200 °C were in the range of 2 to 3 × 10-5 S/cm and the activation energy is about ~0.4 eV. Meanwhile, sample sintered at 1250 °C shows high conductivity that is 8.41 × 10-3 S/cm with 1.4 eV because phenomenon responsible in the sample have grain boundary effect. Therefore, increasing T2 temperature shows high ionic conductor with electrically insulative behaviour that contribute by larger formation of grain growth. 2016 2023-02-16T08:06:42Z 2023-02-16T08:06:42Z Thesis http://dspace.unimap.edu.my:80/xmlui/handle/123456789/77862 en Universiti Malaysia Perlis (UniMAP) Universiti Malaysia Perlis (UniMAP) School of Materials Engineering
institution Universiti Malaysia Perlis
building UniMAP Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaysia Perlis
content_source UniMAP Library Digital Repository
url_provider http://dspace.unimap.edu.my/
language English
topic Fuel cells
Transparent ceramics
LaYO₃
Solid electrolyte
Polycrystalline ceramics
spellingShingle Fuel cells
Transparent ceramics
LaYO₃
Solid electrolyte
Polycrystalline ceramics
Najwa Shafiqa, Anwar
Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃
description Master of Science in Materials Engineering
author2 Mohd Sobri, Idris, Dr.
author_facet Mohd Sobri, Idris, Dr.
Najwa Shafiqa, Anwar
format Thesis
author Najwa Shafiqa, Anwar
author_sort Najwa Shafiqa, Anwar
title Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃
title_short Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃
title_full Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃
title_fullStr Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃
title_full_unstemmed Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃
title_sort studies on the densification and grain growth mechanisms of polycrystalline ceramic based on layo₃
publisher Universiti Malaysia Perlis (UniMAP)
publishDate 2016
url http://dspace.unimap.edu.my:80/xmlui/handle/123456789/77862
_version_ 1772813063486963712
score 13.222552

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