An approach using ceramic shaping by gel-casting and addition of natural tropical fibres as burnable pore developers has been explored for development of porous alumina materials with predetermined pore structures. The fibres used have been characterized in terms of size, shape, water uptake and surface charge. The degree of fibres loading in slurry has been varied. It has been shown that the amount of added fibres correlates well with the measured porosity, the shape of the developed pores however deviating slightly with that of the introduced fibres. The ceramic bodies have been characterised in terms of porosity, shrinkage and flexural strength. It could be assumed that at fibres amount in slurry above 30% V, an open porosity appears which is accompanied by a sharp drop in strength. In order to explore the benefits of the gel-casting method for complex bodies development, two key issues need to be addressed: air evacuation prior to casting and lowering slurry viscosity at fibre loadings higher than the tested ones. For reaching the latter objective, surface modification of fibres has been undertaken.
Gel-casting Porous ceramics Natural fibres
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