A Study on the Effect of Dopant on the Densification and Mechanical Properties of Zirconia Based Ceramic

Wong, Chin Yuan (2016) A Study on the Effect of Dopant on the Densification and Mechanical Properties of Zirconia Based Ceramic. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Due to the increasing demand and development of solid oxide fuel cells (SOFC) and its product, it is important to study the optimum parameters (sintering temperature, effects of different dopants, and operating temperatures) to produce the desired mechanical properties for the SOFC application. These relevant information helps the SOFCs industries with cost efficient way to achieve lower operating temperature without losing the high electrical efficiencies as high operating temperature poses disadvantages to the surrounding and to the SOFC itself. In this research the effects of using different composition of dopants was manipulated in order to control and monitor the affected mechanical properties of the electrolytes used in SOFCs applications. In the present work, the effect of cerium oxide and manganese oxide doping on the mechanical properties and densification of scandia-stabilised zirconia sintered at 1600oC was investigated. The comparison between ceria-scandia-stabilised zirconia (ScCeSZ) produced through co-precipitation and solid state mixing was also studied. Vickers Hardness test, fracture toughness test, and SEM/EDX were carried out to determine the effects influencing the properties of the electrolytes in SOFCs. Results shows that ceria doping is able to stabilise the cubic phase from rhombhedral at room temperature. Other than that, MnO2 doping negatively affected the properties of the ScCeSZ (Highest recorded of 7.84% reduction in density, 29.86% reduction in Vicker hardness, 8.68% reduction in fracture toughness). Results also revealed that the co-precipitation method had shown to have better effect compared to solid state mixing method for the zirconia ceramic with improved sinterability, density (8.51% higher), Vickers hardness (87.29% higher), and fracture toughness.