Hierarchical self-assembly of Zirconium toughened Alumina based bioinspired microporous material by freeze casting method

Herein, we have fabricated the microporous nacre materials with the aid of the Zirconium Toughened Alumina (ZTA) and the glass phases of silica and calcia via the simple freeze casting process in the absence of electro/magnetic assistance or additives. The structure of self-assembled microporous nacre is formed at a defined interval. Notably, the width of the porous material is ~ 3 µm and the mineral bridges displayed a length of ~ 7 µm. This self-assembled microporous material showed enhanced flexural strength (360 MPa), flexural modulus (320 GPa), toughness (~ 420 MPa), fracture toughness (KIC) 8.2 MPa m1/2 and capacity to withstand its mechanical strength even at high temperatures. In addition, compared with the microporous nacre we have engineered various microstructures, such as the nacre structure with nano-asperities, nacre with organic layers, thin fibrous lamellar self-assembled structures with alumina mineral bridges, and the thick scaffold assembly of cellular and lamellar morphology of ZTA by altering the composition of ZTA. Best of our knowledge, this is the first report about the fabrication of ZTA-based self-assembled microporous material with improved mechanical strength by using a simple freeze casting method. This tailor-made microporous nacre assembly processing approach simplified the material fabrication process without magnetic and electrical fields with a simple cost-effective experimental setup.