Highly porous ZrO2 ceramics fabricated by a camphene-based freeze-casting route: Microstructure and properties

A camphene-based freeze-casting method was adopted to create ceramics with aligned, equiaxed pores applied so far exclusively for ceramics—is demonstrated for ZrO2 porous ceramics. The pore volume fraction, channel size and pore shape were controlled by varying the freezing temperature, solid content and sintering condition. After sublimation of camphene, the samples were sintered for 2 h at elevated temperatures ranging from 1400 to 1550 °C. The initial level of solid loading played a primary role in the resulting porosity of the product. The porosity decreased from 82.5 to 65.5 vol.% when the solid loading was increased from 10 to 20 vol.%. The relationship of the compressive strength versus initial solid loading and sintering temperature was discussed. This technique is considered potentially useful in fabricating novel porous ceramics with special structure, and introduces a new application field of freeze-casting.