Nacre-like ceramic refractories for high temperature applications

High-temperature ceramics, so-called refractories, are widely used for the manufacturing of metals, for energy generation and aerospace applications. Refractories are usually strong and stiff but fragile due to the lack of plastic deformation and other intrinsic toughening mechanisms. This inherent brittleness limits their use in applications where catastrophic failure is not tolerated. The present work reports the design and fabrication of refractories with a bio inspired nacre-like microstructure comprising aligned alumina platelets, separated by an aluminium borate interphase, obtained through transient liquid phase sintering. The bioinspired composites exhibit high strength, 672 MPa, toughness, 7.4 MPa m(1/2), and stable crack propagation at high temperatures, above 600 degrees C, due to the aluminium borate interlayer. This makes nacre-like ceramic refractories sintered with a transient liquid phase good candidate for high temperature applications, competing favourably with ceramic. matrix composites and following a simpler and cheaper processing route.