Design and fabrication of porous ZrO2/(ZrO2 + Ni) sandwich ceramics with low thermal conductivity and high strength

• A new structural/functional ZrO2/(ZrO2 + Ni) sandwich ceramics were fabricated.
• The sandwich ceramics attained low thermal conductivity and high strength.
• The effect of sandwich structure on the mechanical behavior was investigated.

3Y–ZrO2/(3Y–ZrO2 + Ni) sandwich ceramics were fabricated through cold isostatic pressing and pressureless sintering. Porous 3Y–ZrO2 ceramics with large connecting open pores and permeability were used as interlayers for insulation, whereas outer metal–ceramic layers were used as bearing loads. Microstructures and properties of the porous ZrO2 and ZrO2/(ZrO2 + Ni) sandwich ceramics were investigated in detail. The ZrO2/(ZrO2 + Ni) sandwich ceramics exhibited better mechanical properties than the monolithic porous ZrO2 ceramics at the same low thermal conductivity (approximately 0.85 W/m K). The mechanical properties of the sandwich ceramics were influenced by metal toughening and sintering-induced residual thermal stress.