Ceramics Sintered Directly from Sol-Gels

Sol-gel technology has been extensively utilized for processing nuclear fuel pellets and powders. Currently, the direct firing of gels is being explored to produce ceramics without the use of any intervening powder steps as an extension of Youldas’ work on glasses and polycrystalline oxides.1 This is motivated by (1) the high purity and homogeneity available in sols; (2) the potential ability in a viscous liquid to minimize the sources of defects introduced in the processing of powders; (3) the ability to visually examine many gel products for defects after drying; and (4) the shaping potential offered by a “plastic” gel. Furthermore, much lower temperatures can be used to fire gels to a fully dense ceramic (e.g., Tho2, Ref. 2) than are required for conventional powder processed bodies.