Evaluation of Toughness Of 0.2, 0.5 and 1.0 WT% CUO Doped Zirconia Using Different Methods

Ong, Khor Jin (2019) Evaluation of Toughness Of 0.2, 0.5 and 1.0 WT% CUO Doped Zirconia Using Different Methods. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Background: Zirconia-based ceramics are routinely used in structural applications in engineering, such as in the manufacture of cutting tools, gas sensors, refractories and structural opacifiers. To meet structural demands, zirconia is doped with stabilizers to achieve high strength and fracture toughness. Objectives: The fracture toughness of 0.2, 0.5 and 1.0wt% Copper Oxide (CuO) doped zirconia using different methods at different microwave sintering temperature are investigated. Moreover, the relationship of fracture toughness as compared with the density, phase stability and grain size of the ceramics is evaluated. Method: The dependence of fracture toughness on microstructure coarsening, induced by different sintering temperatures, has been studied in zirconia±CuO composites with different concentration of dopant of 0.2 wt%, 0.5 wt% and 1.0 wt%. The fracture toughness has been evaluated using different methods based on producing small surface cracks by Vickers indenters, or on producing a large through the thickness crack. It is concluded that fracture toughness increases with the high tetragonal phase content of zirconia. This is explained by the effect of these microstructural parameters on the main operating toughening mechanism, which is found to be stress-induced phase transformation. Results: The fracture toughness values for 0.2 wt% and 0.5 wt% CuO doped sample were higher than undoped sample, while the values for 1.0 wt% CuO doped sample wes lower compared to undoped sample when sintered at 1200oC. Conclusion: The fracture toughness values of zirconia ceramic samples doped with copper oxide by 0.2 and 0.5 wt% were statistically significant when compared to samples doped with 1.0 wt%.