Pressure Filtration of Zr(Y,Ce)<TEX>$O_2$</TEX> TZP/Mullite Suspensions for the Preparations of Functionally Gradient Materials with Multi-layer

,; ,; ,; ,; ,; ,; ,; ,

J. Korean Ceram. Soc. > Volume 37(7); 2000 > Article

Journal of the Korean Ceramic Society 2000;37(7): 693.

다층 경사기능재료의 제조를 위한 Zr(Y,Ce)$O_2$ TZP/Mullite 현탁액의 가압여과

이상진, 박상희¹, 박홍채², 전병세

경남대학교 신소재 공학부
¹가야대학교 세라믹 공학부
²부산대학교 재료공학부

Pressure Filtration of Zr(Y,Ce)$O_2$ TZP/Mullite Suspensions for the Preparations of Functionally Gradient Materials with Multi-layer

ABSTRACT

Casting behavior of Zr(Y,Ce)O2 TZP/Mullite suspension during pressure filtration was investigated to prepare multi-layered Functionally Gradient Materials(FGM). The dispersion stabilities of each layer suspension were investigated by examination of zeta potential and viscosity. The each suspensions with 20 vol.% solid loading and 100 첸 of viscosity was prepared after fix of the dispersing agent (Sodium hexa-meta phosphate) and the binder (Hydroxyethyl cellulose), and then the cakes were formed at the 2.5 MPa~10.0MPa pressure range. The cake thickness of all suspensions was increased with the square root of time at the constant pressure, and the relations between filtration pressure(P)a nd dehydration rate (Q=dh/dt) showed that the flows of filtrates in the consolidated layers were laminar. The permeabilities were nearly constant during filtration, and kozeny constants(Kc) of the suspensions were 4.8~6.7. These valumes were seen as close to 5, which might be homogeneous particle packing during filtration. On the basis of those data, the multi layered compaction with 9 mm thickness and 52.5% green density was prepared by continuous pressure filtration.

Key words: Pressure filtration, FGM, Permeability, Kozeny constant, Dehydration rate