In recent years, porous PZT ceramics have
been developed using various processing techniques such as
the lost wax replication of a coral skeleton [5], carbon fabrics
[6], mixing of burnable plastic spheres (BURPS) processes [7],
gelcasting [8], etc. Each process leads to the formation of its
own microstructure and properties with varied porosities.
Due to the simplicity, versatility and low cost, the direct
foaming technique is always of great interest to produce
porous ceramics [9]. In this method, air bubbles are incorporated into a ceramic suspension by mechanical frothing to
produce wet foams. Then the foams are dried and sintered to
obtain high-strength porous ceramics. However, wet foams are
thermodynamically unstable systems which undergo continuous Ostwald ripening and coalescence processes in order to
decrease the foam overall free energy, so the wet foams are
usually stabilized by long-chain surfactants or by colloidal
particles. Recently, a sort of ultra-stable wet foams was utilized
In recent years, porous PZT ceramics havebeen developed using various processing techniques such asthe lost wax replication of a coral skeleton [5], carbon fabrics[6], mixing of burnable plastic spheres (BURPS) processes [7],gelcasting [8], etc. Each process leads to the formation of itsown microstructure and properties with varied porosities.Due to the simplicity, versatility and low cost, the directfoaming technique is always of great interest to produceporous ceramics [9]. In this method, air bubbles are incorporated into a ceramic suspension by mechanical frothing toproduce wet foams. Then the foams are dried and sintered toobtain high-strength porous ceramics. However, wet foams arethermodynamically unstable systems which undergo continuous Ostwald ripening and coalescence processes in order todecrease the foam overall free energy, so the wet foams areusually stabilized by long-chain surfactants or by colloidalparticles. Recently, a sort of ultra-stable wet foams was utilized
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