Use of Polymeric and other Organic Additives in Ceramic Slurry Processing for Casting—A Review

Abstract

Polymeric and other organic additives are used in ceramic slurry processing for a wide range of oxides, carbides, nitrides etc as dispersants, flocculants, binders, wetting agents and antifoaming agents. The performance of the additives in effecting the desired purpose depends mainly on their chemical nature and functionality, the nature of mineral surface and the aqueous environment. Therefore, it is necessary to have a thorough understanding of the chemistry of dispersants, flocculants, binders, wetting and antifoaming agents in order to maximize the effectiveness of the polymeric and other organic additives. Apart from the polymeric additives other non-polymeric additives are also used. They may be wetting agents, antifoaming agents or even dispersants.Mutual interactions between the additives in any system are usually considered negligible. In many cases, however, interactions that occur can affect the process and ultimately the product performance. This could be the root cause of some common ceramic defects. This paper presents an overview of the use of polymeric and other organic additives in ceramic slurry processing for casting. The basic principle of interactions between ceramic particle and additives governing the stability of the suspension, wettability of the powder dispersion and workability are also discussed.