Abstract

NIETO, M. Isabel; SANTACRUZ, Isabel  and  MORENO, Rodrigo. CONSOLIDATION OF CERAMICS THROUGH POLYSACCHARIDES GELATION. Rev. LatinAm. Metal. Mater. [online]. 2014, vol.34, n.1, pp.02-27. ISSN 0255-6952.

Near-net shaping of ceramics is a key step in ceramic processing, because in this step a mass of powder is transformed into a piece with the desired geometry and size. During consolidation many defects can be introduced in the piece, so that the control of any stage is necessary to reduce or avoid the presence of defects. The gelation of polysaccharides constitutes one the most interesting consolidation mechanisms for shaping of ceramics due to the relative simplicity of the method, the use of water as liquid medium and the low concentration of additives necessary to obtain the bodies. In this work the main applications of polysaccharides in ceramic manufacturing through a gelation mechanism are reviewed. The chemical structure of the most common polysaccharides and their gelation mechanisms are described, including those yielding chemical gelation, as in the case of alginates in the presence of divalent ions, as well as polysaccharides that gel by a temperature change, either on heating as in cellulose derivatives, or on cooling, as in the case of agar derivatives and carrageenans. The influence of other polysaccharides used for their thickening properties but having an important synergy with gelling polysaccharides is also analyzed. In addition to the structure and the basic gelation mechanisms, several examples showing the influence of polysaccharides on the rheology and shaping of ceramic slurries are presented.

Keywords : Ceramics; Processing; Polysaccharides; Shaping.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )