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The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan

3mol% Yttria stabilized Tetragonal Zirconia Polycrystalline (3Y-TZP) ceramic is one of the most demanding material in biomedical application because it possesses the best combination of mechanical properties, biocompatibility and aesthetic properties. These extraordinary properties were attributed t...

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Main Author:	Nur Nadia, Ahmad Hasan
Format:	Thesis
Published:	2017
Subjects:	TA Engineering (General). Civil engineering (General)
Online Access:	http://studentsrepo.um.edu.my/9152/1/Nur_Nadia_Binti_Ahmad_Hasan.bmp http://studentsrepo.um.edu.my/9152/11/nadia.pdf http://studentsrepo.um.edu.my/9152/
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spelling	my.um.stud.91522021-05-10T01:32:39Z The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan Nur Nadia, Ahmad Hasan TA Engineering (General). Civil engineering (General) 3mol% Yttria stabilized Tetragonal Zirconia Polycrystalline (3Y-TZP) ceramic is one of the most demanding material in biomedical application because it possesses the best combination of mechanical properties, biocompatibility and aesthetic properties. These extraordinary properties were attributed to its transformation toughening mechanism as it provides resistance to crack propagation by externally applied stress as a consequence of phase transformation from tetragonal(t) to monoclinic(m) at room temperature. One major drawback with use of the zirconia is the significant loss in mechanical properties attributed by undesired transformation phase tetragonal to monoclinic(tm) when undergo ageing or low temperature degradation(LTD). The current work investigates the effects of sintering additives, particularly focused on 0.5 wt% manganese oxide (MnO2) and 0.1 wt% alumina (Al2O3), and co-doping both additives together (i.e. MnO2 + Al2O3), on the microstructure and mechanical properties of 3 mol% Y-TZP. The doped powders were prepared by attrition milling and subsequently green samples were sintered in air at temperatures ranging from 1250℃ to 1550°C with 2 hours holding time. The results showed that the dopants have not disrupted the tetragonal phase stability. All the dopants aided sintering at 1250°C but with MnO2 being most effective in promoting densification with samples, recording about 97.6 % relative density. Similar improvement in the mechanical properties was also observed for the doped zirconia. Young’s modulus, Vickers hardness and fracture toughness as high as 192 GPa, 13.6 GPa and 4.6 MPam1/2, respectively were obtained for both, the MnO2-doped and co-doped Y-TZPs, when sintered at low temperature of 1250°C. Microstructural examinations however revealed that the MnO2 dopant promoted exaggerated grain growth when sintered at higher temperatures. In addition, the study also found that LTD phenomena in superheated steam condition was suppressed when average grain size not exceed 0.32 μm, particularly for samples sintered at lower temperature. 2017-02 Thesis NonPeerReviewed application/pdf http://studentsrepo.um.edu.my/9152/1/Nur_Nadia_Binti_Ahmad_Hasan.bmp application/pdf http://studentsrepo.um.edu.my/9152/11/nadia.pdf Nur Nadia, Ahmad Hasan (2017) The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan. Masters thesis, University of Malaya. http://studentsrepo.um.edu.my/9152/
institution	Universiti Malaya
building	UM Library
collection	Institutional Repository
continent	Asia
country	Malaysia
content_provider	Universiti Malaya
content_source	UM Student Repository
url_provider	http://studentsrepo.um.edu.my/
topic	TA Engineering (General). Civil engineering (General)
spellingShingle	TA Engineering (General). Civil engineering (General) Nur Nadia, Ahmad Hasan The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan
description	3mol% Yttria stabilized Tetragonal Zirconia Polycrystalline (3Y-TZP) ceramic is one of the most demanding material in biomedical application because it possesses the best combination of mechanical properties, biocompatibility and aesthetic properties. These extraordinary properties were attributed to its transformation toughening mechanism as it provides resistance to crack propagation by externally applied stress as a consequence of phase transformation from tetragonal(t) to monoclinic(m) at room temperature. One major drawback with use of the zirconia is the significant loss in mechanical properties attributed by undesired transformation phase tetragonal to monoclinic(tm) when undergo ageing or low temperature degradation(LTD). The current work investigates the effects of sintering additives, particularly focused on 0.5 wt% manganese oxide (MnO2) and 0.1 wt% alumina (Al2O3), and co-doping both additives together (i.e. MnO2 + Al2O3), on the microstructure and mechanical properties of 3 mol% Y-TZP. The doped powders were prepared by attrition milling and subsequently green samples were sintered in air at temperatures ranging from 1250℃ to 1550°C with 2 hours holding time. The results showed that the dopants have not disrupted the tetragonal phase stability. All the dopants aided sintering at 1250°C but with MnO2 being most effective in promoting densification with samples, recording about 97.6 % relative density. Similar improvement in the mechanical properties was also observed for the doped zirconia. Young’s modulus, Vickers hardness and fracture toughness as high as 192 GPa, 13.6 GPa and 4.6 MPam1/2, respectively were obtained for both, the MnO2-doped and co-doped Y-TZPs, when sintered at low temperature of 1250°C. Microstructural examinations however revealed that the MnO2 dopant promoted exaggerated grain growth when sintered at higher temperatures. In addition, the study also found that LTD phenomena in superheated steam condition was suppressed when average grain size not exceed 0.32 μm, particularly for samples sintered at lower temperature.
format	Thesis
author	Nur Nadia, Ahmad Hasan
author_facet	Nur Nadia, Ahmad Hasan
author_sort	Nur Nadia, Ahmad Hasan
title	The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan
title_short	The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan
title_full	The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan
title_fullStr	The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan
title_full_unstemmed	The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan
title_sort	effects of sintering additives on the mechanical properties and microstructure evolution of 3 mol% y-tzp / nur nadia ahmad hasan
publishDate	2017
url	http://studentsrepo.um.edu.my/9152/1/Nur_Nadia_Binti_Ahmad_Hasan.bmp http://studentsrepo.um.edu.my/9152/11/nadia.pdf http://studentsrepo.um.edu.my/9152/
_version_	1738506231259070464
score	13.222552

The effects of sintering additives on the mechanical properties and microstructure evolution of 3 MOL% Y-TZP / Nur Nadia Ahmad Hasan

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