Ceramics-Silikáty 58 (2) 99-105 (2014)

MECHANICAL PROPERTIES OF MACROPOROUS SILICON NITRIDE-BASED CERAMICS DESIGNED FOR BONE SUBSTITUTES

Porous silicon nitride preforms designed for bone substitutes were prepared by two different forming methods: by introduction of semolina as pore forming agent and by template method with polyurethane sponge. Silicon nitride-based green bodies were sintered in air at two different temperatures, while the Si + 20 % Si₃N₄ samples were sintered by reaction bonding process in nitrogen. Template method yields samples with interconnected macroporous structure comparable to the bone structure while introduction of semolina results only in isolated macropores formation. All sintered samples were characterized in terms of phase composition and microstructure. Moreover, some of the mechanical properties (hardness, elastic modulus, bending strength) were measured and compared to the bone properties in order to select the most suitable method for the preparation of trabecular bone substitute. Despite of relatively low strength, the template method with subsequent sintering in air appeared to be the most promising way for the preparation of trabecular bone-like silicon nitride-based porous ceramic structures, whereas the hardness and elastic modulus of as prepared samples were in perfect accordance with bone characteristics.

Keywords: Bone substitute, Silicon nitride, Macroporous structure, Mechanical properties