Particle size effect of starting SiC on processing, microstructures and mechanical properties of liquid phase-sintered SiC

摘要: Abstract Dense SiC (97.3–99.2% relative density) of 1.1–3.5 μm average grain size was prepared by the combination colloidal processing bimodal particles with sintering additives (Al 2 O 3 plus Y , 2–4 vol%) and subsequent hot-pressing at 1900–1950 °C. The fracture toughness sensitive to boundary thickness which controlled amount oxide additives. A maximum (6.2 MPa m 1/2 ) measured 20 nm thickness. mixing 30 nm (25 vol%) 800 nm (75 vol%) effective reduce flaw origin, in addition a high toughness, leading increase flexural strength. However, mixture (25 vol%)–330 nm provided too small grains (1.1 μm size), resultant thin boundaries (12 nm), decreased relatively large defect resulting