Title of article :
Particle size effect of starting SiC on processing, microstructures and mechanical properties of liquid phase-sintered SiC
Author/Authors :
Hirata، نويسنده , , Yoshihiro and Suzue، نويسنده , , Naoto and Matsunaga، نويسنده , , Naoki and Sameshima، نويسنده , , Soichiro، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2010
Abstract :
Dense SiC (97.3–99.2% relative density) of 1.1–3.5 μm average grain size was prepared by the combination of colloidal processing of bimodal SiC particles with sintering additives (Al2O3 plus Y2O3, 2–4 vol%) and subsequent hot-pressing at 1900–1950 °C. The fracture toughness of SiC was sensitive to the grain boundary thickness which was controlled by grain size and amount of oxide additives. A maximum fracture toughness (6.2 MPa m1/2) was measured at 20 nm of grain boundary thickness. The mixing of 30 nm SiC (25 vol%) with 800 nm SiC (75 vol%) was effective to reduce the flaw size of fracture origin, in addition to a high fracture toughness, leading to the increase of flexural strength. However, the processing of a mixture of 30 nm SiC (25 vol%)–330 nm SiC (75 vol%) provided too small grains (1.1 μm average grain size), resultant thin grain boundaries (12 nm), decreased fracture toughness, and relatively large defect of fracture origin, resulting in the decreased strength.
Keywords :
Hot-pressing , Toughness and toughening , SiC , Strength
Journal title :
Journal of the European Ceramic Society
Journal title :
Journal of the European Ceramic Society