کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1582626 | 1514876 | 2008 | 6 صفحه PDF | دانلود رایگان |

Hot-pressed silicon carbide composites reinforced with carbon fiber were prepared. Aluminum and yttrium oxides served as sintering additives and low-cost α phase SiC was used as starting powder, instead of the more expensive β-SiC. In the sintering process, the SiC-matrix grains grew larger via solution reprecipitation. Reaction of Al2O3/Y2O3 additives with SiO2 on the surface of SiC or its oxidation products caused formation and distribution of a low-eutectic-point phase around the SiC grains and carbon whiskers. Such amorphous films can be found in triple-junctions and boundaries of SiC grains. Excess sintering additives improve the room-temperature flexural strength, but reduce the fracture toughness. Coupled with a higher sintering temperature, they contribute to the diffusion of yttrium ions into carbon fiber, and make the reaction layer thicker. Non-homogeneous amorphous inclusions between grains and whiskers are harmful for mechanical properties. A combination of grain bridging, crack deflection and whisker debonding can improve fracture toughness.
Journal: Materials Science and Engineering: A - Volume 480, Issues 1–2, 15 May 2008, Pages 62–67