Ceramic membranes tape casting

Tape casting is a well known method for making thin, flat and dense ceramics [13-15]. This technique is limited by the thickness (a few millimetres) of the films obtained. The most important applications are in the electronics industry. Simon et al. [16] have described the preparation of flat ceramic membranes. This type of geometry is receiving interest because of the possibility of obtaining a high module compactness (compactness is defined by the ratio of membrane surface area to module volume). 

The main component of a solid oxide fuel cell is a three-layered sandwich consisting of anode, electrolyte, and cathode, each being made from a different oxide ceramic material. Such ceramic structures can be fabricated by various methods including slip or tape casting, injection molding, ceramic coverings, etc. [1]. Whatever the method applied is, it should provide the best able microstructure and specified performance of materials besides the desired shape of a SOFC membrane. However, layers of the membrane have different properties that requires combination of two or more different methods of ceramic engineering in the component fabrication. 

With respect to 7O2 obtained for the tape-cast membrane at 1000 °C, note that the value was enhanced only 50% compared to those for the bulk specimen, although the membrane thickness was reduced by a factor of about one-half. This implies that the oxygen-permeation flux was limited by surface exchange kinetics rather than ambi-polar diffusion process in ceramics. If this is the case, the Wagner s equation can be modified by including a characteristic thickness of dc as follows (Bouwmeester, Kruidhof, Burggraaf, 1994) ... 

Y. Zhang, C. Qin, and J. Binner. (2006). Processing multi-channel alumina membranes by tape casting latex-based suspensions, Ceram. Int. 32 811-818. 

The thickness of porous ceramic membranes prepared in this manner is typically in the range of a few millimetres (Larbot, 1996), although thinner membranes have been realised (Sahibzada e/a/., 2000).Tape casting is a high volume production technique for fiat sheet membranes and is employed on both a research and commercial scale. 

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