Fabrication and flexural strength of ultrafine-grained yttria-stabilized zirconia

Ultrafine powders of yttria-stabilized zirconia were fabricated into specimens by die pressing, extrusion and slip casting. Gross pores present in unfired specimens varied with fabrication procedure and persisted in the fired microstructures. Pressure-cast specimens with no apparent internal pores larger than grain size and with as-fabricated surfaces containing surface pores approximately 2 ..mu..m exhibited mean flexural strengths as high as 129 kpsi. The ultimate flexural strength of extruded and pressed specimens appeared to be limited by residual coarse pores near the surface, and flexural strengths ranged as low as 16 kpsi.