Production of porous SiC by liquid phase sintering using graphite as sacrificial phase: Influence of SiO2 and graphite on the sintering mechanisms. Issue 14 (November 2019)

• Record Type: Journal Article
• Authors: Soto, C.; García-Rosales, C.; Echeberria, J.
• Is Part Of: Journal of the European Ceramic Society. Volume 39:Issue 14(2019)
• Page Start: 3949
• Page End: 3958
• Publication Date: 2019-11
• Subjects: Silicon carbide -- Liquid phase sintering -- Thermal conductivity -- Sintering additives; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2019.06.022
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Porous silicon carbide (SiC) is a promising ceramic for high-temperature applications due to its unique combination of properties. In the present work, a fabrication route for porous SiC is presented using graphite spherical powder as sacrificial phase to introduce porosity. By varying the initial amount of sacrificial phase, high-performance SiC materials with porosities in the range 30–50% were manufactured and characterized in terms of microstructure, density, thermal conductivity and flexural strength. The materials were fabricated by liquid phase sintering in presence of 2.5 wt.% Al2 O3 and Y2 O3 as sintering additives. The results indicate that the SiO2 present in the starting SiC powders interacts with the sintering additives forming liquid phases that promote densification and weight loss. Besides, an Al-Si liquid phase is formed at higher sintering temperatures, whose contribution to densification is inhibited in presence of graphite due to the formation of Al-rich carbides.