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

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...

Full description

Saved in:

Bibliographic Details
Format:	Thesis
Language:	English
Subjects:	Fuel cells Transparent ceramics LaYO₃ Solid electrolyte Polycrystalline ceramics
Online Access:	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/2/Full%20text.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/4/Najwa%20Shafiqa.pdf
Tags:	Add Tag No Tags, Be the first to tag this record!

id	my-unimap-77862
record_format	uketd_dc
spelling	my-unimap-778622023-02-16T08:09:28Z Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃ Mohd Sobri, Idris, Dr. 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. Universiti Malaysia Perlis (UniMAP) Thesis en http://dspace.unimap.edu.my:80/xmlui/handle/123456789/77862 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/3/license.txt 8a4605be74aa9ea9d79846c1fba20a33 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/1/Page%201-24.pdf 623ecd5f4d427920d5e3854a9c9789f4 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/2/Full%20text.pdf 02ca330c3d49979c171533782a3c2dcb http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/4/Najwa%20Shafiqa.pdf a805be98f806867ba550ee5a4dedcb28 Universiti Malaysia Perlis (UniMAP) Fuel cells Transparent ceramics LaYO₃ Solid electrolyte Polycrystalline ceramics School of Materials Engineering
institution	Universiti Malaysia Perlis
collection	UniMAP Institutional Repository
language	English
advisor	Mohd Sobri, Idris, Dr.
topic	Fuel cells Transparent ceramics LaYO₃ Solid electrolyte Polycrystalline ceramics
spellingShingle	Fuel cells Transparent ceramics LaYO₃ Solid electrolyte Polycrystalline ceramics Studies on the densification and grain growth mechanisms of Polycrystalline ceramic based on LaYO₃
description	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.
format	Thesis
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
granting_institution	Universiti Malaysia Perlis (UniMAP)
granting_department	School of Materials Engineering
url	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/2/Full%20text.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/77862/4/Najwa%20Shafiqa.pdf
_version_	1776104235611455488

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

Similar Items