Development of elongated 6H-SiC grains in reaction-bonded porous SiC ceramics

Porous 6H-SiC ceramics were fabricated at a low temperature by an in situ reaction bonding process. After subsequent heat treatment, porous SiC ceramics with elongated 6H-SiC grains and improved strength were obtained. The results indicated that in situ growth of elongated 6H-SiC grains was caused by rare earth elements together with the liquid Ba–Al–Si–O system. The type and content of rare earth oxides had a large influence on the growth of elongated 6H-SiC grains.