The Influence Of T-ZrO₂ Addition On The Mechanical Property And Electrical Conductivity Of YSZ Electrolyte

The electrolyte material based on ZrO2 had been researched in tensing by many scholars. The 8YSZ material that has a high electrical conductivity is widely used as electrolytes for solid oxide fuel cells (SOFCs). But its low strength and low fracture hampered the development of SOFCs. Enhancing the mechanical property with a proper electrical conductivity had become more and more important to meet the need of the development of SOFC.In order to find a best method to improve the capability of YSZ electrolyte, the effects of 3Y-TZP additive on the density, strength, conductivity and microstructure were studied by means of X-ray diffraction and Vicker's hardner. The strength and conductivity of YSZ electrolyte doped with different amount of 3Y-TZP were determined.It was shown that the samples sintered at 1450°C for 2h were the best in properties. When 3Y-TZP powder was added to the YSZ system, the tetragonal phase ratio increased, which resulted in non-uniform doping of Y2O3 into the ZrO2 grains and abnormal grain growth occurred for the sample with a higher Y2O3 content. The results demonstrated that strength of the electrolyte increased remarkably, and the fracture toughness got improved. The electrical conductivity was lowered only slightly. The results displayed that the flexure strength and the fracture toughness of ceramics with 30% TZP reached 300MPa and 3.7MPa·m1/2 respectively, and the conductivity at 1000°C reached 0.11S·cm-1.