Resumo

PEREIRA, Maria Janeth; RODRIGUEZ, Rosa; MUCI, Cristina  e  MILLAN, Arnaldo. Conformation of dense/porous structures by straining aqueous suspensions with agarose for application in sofc cells. uct [online]. 2008, vol.12, n.47, pp.107-112. ISSN 1316-4821.

Solid Oxide Fuel Cells have a “sandwich”-type configuration, a dense nucleus confined between two porous surfaces. They are conformed by various methods, such as Type Casting/Screen Printing or Tape Calendaring, which are not totally effective since the efficiency of the device diminishes on time while the ohm resistance in the plane of the electrolytes/electrodes interface increases, or they are very costly. A possible solution to this problem would be to eliminate said interface. This is possible applying a process such as the straining or injection of colloidal suspensions in a metallic mold at a low temperature. Consequently, this work proposes the application of this methodology in alumina aqueous suspensions adding agarose to produce dense/porous bodies without interface and using diverse techniques to generate porosity. A porous region was obtained, with pore diameter lower than 100 μm, and a dense region close to 98% of densification, without interface between them. The distribution of pores was not very adequate, but the diameter of pores was acceptable for the application in these devices. Alumina was used to verify the versatility of the method and as reference for subsequent application to materials such as zirconia stabilized with ytria.

Palavras-chave : Conformation Processes; Dense Porous Structures; SOFC Cells; Aqueous Suspensions with agarose.