The effect of shape forming and sintering methods on properties of 8 mol%-Y2O3 stabilized nano structured zirconia bodies

Among different types of ceramics, 8 mol%-Y2O3 stabilized zirconia (8YSZ) because of its high oxygen ioni c conductivity and chemical stability over a wide range of temperature is a well known candidate for oxide fuel cells. In the present study, the effect of different shaping method on densification and grain growth of 8YSZ was studied. The slip casting was shown to be a more efficient method yielding homogenous green bodies with higher green density containing smaller pores with narrower distribution. The grain growth, consequently, was decreased significantly in nearly-full dense bodies formed by slip casting. Two steps sintering of nanocrystalline powder resulted in remarkable suppression of accelerated grain growth. High rate microwave sintering was also found to hinder the grain growth, resulting in finer microstructure. The fracture toughness and microhardness were taken as criteria to evaluate the microstructural evolution of 8YSZ bodies formed by different combination of shape forming-sintering methods. Interestingly it was shown that without applying any modified sintering technique the hardness and fracture toughness of slip casted bodies with coarser structure is completely close to those of samples sintered through microwave heating

Keywords:

Zirconia , Nanostructured , Shape forming