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Using Porosity

Open or connected porosity applications utilize the pore size and path length [usually part thickness] to control fluid transfer rate or maximum particle size transmission.  The pore size and surface chemistry affect the configuration of the transmitted fluid upon exiting the part [bubble or droplet size].  A secondary effect is the lowering of strength as a function of % porosity.  This strength can be enhanced or lessened by proper design.  Some applications require a strong part to survive processing; other applications require controlled failure to enhance timely extraction of ceramic.

Very open porosity allows high fluid passage rates with very low pressure drops.  This is useful for mechanically supporting other structures without inhibiting flows.  Catalysts are often high surface area but low mechanical strength which can utilize the porous ceramic support.

Closed porosity provides several performance effects that can be controlled by design.  Within limits the part mass can be reduced with little lessening of strength or wear resistance.  Thermal conductivity can be reduced dramatically with closed pore control, size, amount, and distribution gradient.

 Depending on body, application the per cent porosity can range for 0 to 85%.