Ceramic suspensions filter pressing

See CRYSTAL structure fracture. (2) A suspension in water of clay and/or other ceramic materials normally a DEFLOCCULANT (q.v.) is added to disperse the particles and to prevent their settling out. In the whiteware industry, a slip is made either as a means of mixing the constituents of a body (in which case it is subsequently dewatered, e.g. by filter-pressing) or preparatory to CASTING (q.v ). In vitreous enamelling, a slip is used for application of the enamel to the ware by spraying or dipping. 

Filtering the tube suspension through a 0.2 xm pore ceramic paper leaves a uniform black deposit on the paper and can produce aligned CNT films [30]. The deposited material was transferred on a thin Teflon sheet by pressing the tube-coated side of the filter on the plastic and then the filter was lifted off to expose the surface. Scanning electron microscopic study reveals that the tubes are highly aligned perpendicular to the Teflon surface [30]. 

In earlier research the alignment operation was applied to CNTs in the form of a CNT-polymer resin [24] or CNT suspended in a solvent [25]. In the method developed by Ajayan et al. [24], purified MWCNTs were dispersed in an epoxy resin which was cut with a diamond knife and a microtome in order to obtain aligned CNTs. De Heer et al. [25] used a 0.2 (im pore ceramic filter in order to create an MWCNT suspension in ethanol, and to obtain a black deposit which was transferred to a plastic surface (Delrin or Teflon) by pressing the filter onto the polymer. However, only a moderate degree of orientation and uniformity in length of the CNTs was achieved by this method. 

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