Mullite-alumina nacre-like ceramic fabricated by ceramic vat photopolymerization

Abstract

Current investigations have studied using alumina platelets combining with hot press sintering or infiltration process to fabricate toughened nacre-like composite ceramics, while there is still a lack of research on the fabrication of nacre-like ceramics using vat photopolymerization and pressureless sintering. We utilized the gradient shear stress in the local slurry flow in the vat photopolymerization printing to horizontally orient the alumina platelets in the slurry, and then prepared mullite-alumina nacre-like ceramics by combining the template grain growth and the in-situ reaction of SiO₂-Al₂O₃. When the content of alumina platelet accounted for 20 vol%, the bending strengths of load parallel to the printing direction and perpendicular to the printing direction were 344 ± 20 MPa and 352 ± 24 MPa, respectively. The fracture toughness were 3.57 ± 0.38 MPa.m^1/2 and 3.37 ± 0.24 MPa.m^1/2, respectively. The prepared nacre-like structure had the effect of crack deflection and crack twisting in the fracture surface.