Improvement in the specific strength by arranging closed pores in fully densified zirconia ceramics

A novel porous ceramics with a specific mechanical strength higher than monolithic dense ceramics was reported. Three types of composite granules with different-sized cores of a foam agent coated with a matrix powder were used in the study. These superplastic-foamed porous ceramics pores with many closed pores were prepared by compaction followed by sintering. It was observed during the study that the bending strength of the fabricated ceramics with the smallest pores was nearly equal to half of fully dense cores with a porosity of 27%. It was also found that the mechanical strength of superplastic-foamed porous ceramics increased with the decrease of pore size. The study concluded that the finished dense/porous/dense layered ceramics showed a specific mechanical strength higher that monolithic dense ceramics.