Time-dependent properties of ceramic suspensions
- IRTEC, Faenza (Italy)
- Univ. of Trieste (Italy)
Ceramic processing deals with suspensions either for powder handling and treating or for cold consolidation. In the industrial processing ceramic powders are milled in water, stored as suspensions and spray dried into granules to improve flowability for the following dry pressing stage or partially drained for working in the plastic state or they can be consolidated from the suspension state itself through casting techniques. Glazes are mostly prepared and spread as suspension. Suspension is the term generally used for traditional ceramics which body is made of a combination of several raw materials with a broad range of particle sizes from several tens of microns to the colloidal range; dispersion is a more appropriate term for advanced ceramics where the particle size distribution is mostly confined in the colloidal range. The industrial control of the process is frequently reduced to simple routine tests on parameters of the suspension like pH, conductivity, apparent density and viscosity in fixed conditions and the viscometers employed are frequently non absolute apparatus but only semi-empirical devices. The rheological behavior of the suspensions is very complex and the response obtained from a {open_quotes}viscosity{close_quotes} measurement, which is considered as the key rheological quantity, depends on many intrinsic parameters of the suspension but also on the viscometer characteristics and testing procedure. In fact the flowing properties depend on particle physics, interfacial chemistry and rheological parameters which determine the particle-particle collision and friction energy transfer and particle - fluid hydrodynamics. Rheometry deals with simple flows like the steady shear flow, the small amplitude oscillatory - shear flow and the extensional flow which can be considered a strong flow and finds many practical applications. In this paper we refer only to shear flow.
- OSTI ID:
- 181775
- Report Number(s):
- CONF-940416-; TRN: 96:000418-0002
- Resource Relation:
- Conference: 96. annual meeting of the American Ceramic Society (ACS), Indianapolis, IN (United States), 25-28 Apr 1994; Other Information: PBD: 1995; Related Information: Is Part Of Ceramic transactions: Science, technology, and applications of colloidal suspensions. Volume 54; Adair, J.H.; Casey, J.A.; Randall, C.A.; Venigalla, S. [eds.]; PB: 285 p.
- Country of Publication:
- United States
- Language:
- English
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