Nacre-like alumina composites reinforced by zirconia particles.

• Nacre-like composites were prepared with a simple process, including zirconia particles in monoclinic or in tetragonal phase. • A R-curve effect is noted for all samples, mainly driven by crack deflection along the platelet interfaces. • The addition of tetragonal zirconia increases the strength and limits the growth of alumina grains during sintering. • Composites with tetragonal zirconia and no glass phase are potential candidates for high temperature applications. Nacre-like alumina is a class of bio-inspired ceramic composite manufactured by field-assisted sintering of green bodies made primarily of alumina platelets with an anisotropic microstructure. Here we investigate the addition of zirconia particles to enhance the mechanical properties of the composite. The resulting structure is a nacre-like anisotropic structure which features deflection and reinforcement during crack propagation. Monoclinic zirconia has no impact on the mechanical properties of the composite while tetragonal zirconia improves its fracture resistance properties. Both types of zirconia seem to slow down grain growth during sintering. The addition of zirconia stabilised in the tetragonal phase is thus a good option to obtain a composite with a fine microstructure and higher mechanical properties than a standard nacre-like alumina, with a flexural strength of 626 ± 39 MPa and a crack initiation toughness of 6.1 ± 0.6 MPa.m0.5. [ABSTRACT FROM AUTHOR]