Fabrication, chemical etching, and compressive strength of porous biomimetic SiC for medical implants

BioSiC is a biomimetic SiC-based ceramic material fabricated by Si melt infiltration of carbon preforms obtained from wood. The microstructure of bioSiC mimics that of the wood precursor, which can be chosen for tailored properties. When the remaining, unreacted Si is removed, a SiC material with interconnected porosity is obtained. This porous bioSiC is under study for its use as a medical implant material. We have successfully fabricated bioSiC from Sipo wood and studied the kinetics of Si removal by wet etching. The results suggest that the reaction is diffusion-limited, and the etch rate follows at^−0.5law. The etching rate is found to be anisotropic, which can be explained attending to the anisotropy of the pore distribution. The compressive strength was studied as a function of etching time, and the results show a quadratic dependence with density. In the attainable range of densities, the strength is similar or better than that of human bone.