Additive-free hot-pressed silicon carbide ceramics-A material with exceptional mechanical properties

Journal Article · Wed Dec 30 00:00:00 EST 2015 · Journal of the European Ceramic Society

DOI:https://doi.org/10.1016/j.jeurceramsoc.2015.12.013· OSTI ID:1266860

Sajgalik, P. ^[1]; Sedlacek, J. ^[1]; Lences, Z. ^[1]; Dusza, J. ^[2]; Lin, H. -T. ^[3]

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1. Slovak Academy of Sciences, Bratislava (Slovakia)
2. Slovak Academy of Sciences, Kosice (Slovakia)
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Densification of silicon carbide without any sintering aids by hot-pressing and rapid hot pressing was investigated. Full density (>99% t.d.) has been reached at 1850 °C, a temperature of at least 150-200 °C lower compared to the up to now known solid state sintered silicon carbide powders. Silicon carbide was freeze granulated and heat treated prior the densification. Furthermore, evolution of microstructure, mechanical properties and creep behavior were evaluated and compared to reference ceramics from as received silicon carbide powder as well as those of commercial one. Novel method results in dense ceramics with Vickers hardness and indentation fracture toughness of 29.0 GPa and 5.25 MPam^1/2, respectively. Moreover, the creep rate of 3.8 x 10^–9 s^–1 at 1450 °C and the load of 100 MPa is comparable to the commercial α-SiC solid state sintered at 2150 °C.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1266860
• Journal Information: Journal of the European Ceramic Society, Vol. 36, Issue 6; ISSN 0955-2219
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
silicon carbide
hot pressing
microstructure
mechanical properties
creep resistance