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

Abstract

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 a t−0.5 law. 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.

Microstructural and mechanical evaluation of porous biomorphic silicon carbide for high temperature filtering applications

“…There are previous studies of the compressive strength of these materials for a wide range of etching time and temperatures. 31 In this work, we complete these previous results with data obtained in the most unfavorable conditions: high temperature, silicon etched away, and load application by bending. Fig.…”

“…The anisotropic advance of etching front, and weight loss as a function of the chemical etching on bioSiC, has been characterized in detail in a previous publication. 31 In the case of porous sipobioSiC, the microstructure resembles that of the sipo wood, a combination of large channels optimized for fluids transport and small channels that give structural strength at low density. Porous MDF-bioSiC microstructure is more uniform and isotropic, corresponding with the microstructure of the wood fibers that compose the MDF precursor.…”

New Bio-ceramization process applied to vegetable hierarchical structures for bone regeneration: an experimental model in sheep.

“…1a-e). 43 A similar approach to reproduce the spongy part of bone has been carried out for the past decade, by reproducing in a laboratory the biomineralization processes that in vivo lead to the formation of new bone tissue. 21,69 In this regard, hybrid hydroxyapatite/collagen composites were developed, where the mineral phase was heterogeneously nucleated on the selfassembling collagen fibers in a specific manner, due to several control mechanisms (i.e., chemical, physical, morphological, and structural) acting at different dimensional ranges, from the molecular up to the macroscopic scale.…”

“…21,69 In this regard, hybrid hydroxyapatite/collagen composites were developed, where the mineral phase was heterogeneously nucleated on the selfassembling collagen fibers in a specific manner, due to several control mechanisms (i.e., chemical, physical, morphological, and structural) acting at different dimensional ranges, from the molecular up to the macroscopic scale. 43 This led to the development of commercial products (i.e., RegenOss Ò , MaioRegen Ò ) for the regeneration of bone and osteochondral tissues.…”

“…The scaffold was obtained by biomorphic transformation of Sipo wood (Entandophragma utile), following a procedure reported elsewhere. 43 In brief, blocks of Sipo wood were pyrolized by heating at 800°C under a flowing argon atmosphere (0.5°C/min heating rate) to obtain a woodderived carbon template (Fig. 1b) that was subsequently machined to a hollow cylinder using a lathe.…”