Digital Repository, CONVEGNO IGF XXII ROMA 2013

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Toughening of silicon carbide-based materials
G. Magnani, A. Brentari, S. Galvagno, G. Sico

Last modified: 2013-06-27


Silicon carbide sintered samples with the same density and different microstructure were obtained
through different sintering procedures. The “two-step sintering” method was useful to achieve SiC basedmaterials
characterized by finer microstructure than those obtained with the conventional sintering process.
This was demonstrated with both solid-state sintering (with boron and carbon as sintering additives) and liquidphase
sintering (with alumina and yttria as sintering additives). The finer microstructure enhanced the fracture
toughness of the materials. The toughening mechanism was different: change in the fracture mode from
transgranular to intergranular in the solid-state sintered material and improvement of the crack deflection
mechanism in the liquid-phase sintered samples. The highest value of fracture toughness (7 MPa m1/2) was
reached with a very fine powder produced using waste tires as carbon source and quartz.

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