Processing of porous yttria-stabilized zirconia by tape-casting

Abstract

The tape-casting process was used to produce porous yttria-stabilized zirconia (YSZ) substrates with pore volume fraction from 14 to 44.7% using starch as a fugitive additive. Concentrated aqueous YSZ slips with different amounts of starch and an acrylic latex binder were prepared. The influence of the slip composition on the properties of green and sintered tapes were studied. In addition, the pore structure and final microstructure were investigated. The YSZ packing density of the tapes with amounts of starch from 13 to 33 wt% was dependent on the latex that remained between the YSZ particles, which was, in turn, controlled by the added latex and starch. The volume of starch in the green tape and consequently the volume fraction of porosity in the sintered tape could be controlled by the amount of starch added as well as by the latex content. As the volume fraction of starch increased from 17 to 33% there was a gradual increase in the openness of the pore structure; for 33 vol.% starch the porosity was completely open. The sintering shrinkage was dependent on the green density; for a constant amount of starch, the additional porosity created by the latex volume was removed upon sintering resulting in an increase in the sintering shrinkage.