Gelatin tailored pore structure and mechanical properties of freeze-cast porous boron carbide ceramics

The architectures of porous B₄C scaffolds play a pivotal role in the performance of their infiltrated composites for multiple applications. Here, we use gelation-freeze-drying approach to creating the porous B₄C scaffolds with oriented channels, which are promising and relatively untested freeze-cast constructs. Addition of gelatin alters not only the porosity and shrinkage but also the pore size and morphology of the scaffolds. Specifically, as gelatin contents increase from 0 to 5 wt%, the porosity, closed porosity, and volume shrinkage range from 74.53 to 73.27%, 0.28–0.65% and 1.95–3.96%, respectively; the increased wavelength and lamellar thickness can be attributed to the enhancement in viscosity. Importantly, raised gelatin contents lead to the reduced pore aspect ratio triggering the transformation from lamellae with a high aspect ratio to ellipse shaped morphologies that contribute to the improved compressive strength ranging from 0.7 to 4.4 MPa. The freeze-cast B₄C scaffolds with tailored performance by varying gelatin contents widen the application scopes of bioinspired composites.