Tailored microstructures by multi-component pressure filtration

A novel apparatus for computer controlled pressure filtration has been
constructed. The precise flow rate of multiple ceramic suspensions of
different compositions can be controlled. Suspensions are mixed before
entering the filtration chamber. By dynamically adjusting the different
flow rates, phase compositions anywhere between 100% phase A to 100%
phase B can be realized as a function of the filter cake height with
filtration pressures of up to 10 MPa. This is suitable for producing
functionally graded materials with smooth changes of composition or
layered structures where the changes are steep. Gradients and layers in
porous alumina and in alumina-zirconia have been produced and
investigated. The process is suitable for all materials that can be
handled by slip casting.