Slurry cast process

FIGURE 2. Schematic representation of the various methods for producing HiPeiComp MI CMCs. The bold black highlighted path represents the piepteg process and the highhghted bold gray path represents the slurry cast process. (Reprinted by permission of ASME Press.)... 

According to published information [52, 54, 58] two methods are in use (1) powder casting process, and (2) slurry casting. 

The slurring methods have the advantage of greater simplicity and versatility, and lower cost than the standard casting process(Ref 3 P 251) Slurrying methods have been used in prepn of some cast composite proplnts (See also AddnlRefs g,h,j,l m) ... 

Figure 7.24 Slip-casting process (a) a mold, which contains a cavity of the desired shape, is prepared (b) the slip, a slurry or suspension of particles, is poured into the mold (c) liquid is absorbed by the mold, compacting the slip s particles on the mold walls via capillary forces (d) when a cast layer of desired thickness has been built up, the remaining slip is poured out of the mold (e) after drying, the slip-cast part is removed from the mold, which is then dried for reuse.

Although tape casting is in many ways similar to slip casting, there are a few important differences. Since the goal is to produce thin—in some cases, extremely thin—sheets, the particulate or powder used to make up the slurry is typically finer than you would see in most slip-casting operations. Second, tape-casting processes typically utilize a nonporous substrate. This necessitates... 

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A major difference between the two methods is the process by which the liquid is removed from the slurry. In slip casting, the liquid is removed by capillary suction provided by a porous mold. In contrast, the liquid is removed by evaporation in tape casting. In most tape casting processes, the liquid is nonaqueous because the higher volatility allows faster evaporation. 

Fig. 4 Schematic of the slip casting process for a ceramic shape. A slurry of ceramic particles and a carrier fluid is poured into a porous mold. The carrier fluid flows into the pores of the mold, and the ceramic particles remain behind and build up a solid cake in the mold. After the fluid has drained from the part, the cast shape can be removed from the mold.

Fig. 6 Schematic of a tape casting process used to form thin sheets of ceramic material. The slurry of ceramic particles and carrier fluid flows beneath the doctor blade onto a moving carrier film. As the tape moves down the bed, it dries and is then spooled on a take up reel.

The stable dispersion of slurry is required to casting process. Thus, we investigate the interaction between starting materials and other organics by measuring electrokinetic sonic amphtude(ESA, MBS-8000, Matec Apphed Sc., U.S.A) and the rheology of slurry with viscometer(Brookfield DV-II). Therefore, the optimal condition for dispersion was determined. The compacted green sheets with various composition are sintered and then characterized. 

For the gel-casting process, the solid loading of a slurry has a direct influence on the density of the green parts. On the other hand, a low viscosity of the slurry is beneficial for both milling and casting processes. Therefore, it is important to achieve a solid loading as high as possible while... 

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