FORMING PROCESSES OF STRONTIUM BARIUM NIOBATE CERAMICS

In forming strontium barium niobate (SBN) ceramics, two methods (press ure filtration and slip casting) were employed to investigate the cons olidation behaviour. The zeta potentials were measured to understand t he interparticle forces of SBN powders. It was found that the zeta pot entials of SBN powders were negative above pH 2.2. Several experiments have been conducted to investigate the effect of pH on the theologica l behaviour of SBN slurries with 20 vol % solids loading. The theologi cal behaviour of the slurries SBN with 20 vol % solids loading at pH 1 1.5 is shear thinning. It is suggested that the increase of the flow r ate of the fluid might have the advantages to enhance the packing dens ity and prevent fine particles from clogging in pressure filtration an d slip casting. Two different moulds i.e. plaster and alumina have bee n used to investigate the effect of pore morphology of the moulds on t he cake microstructures. A uniform microstructure of cast cake was for med for using an alumina mould and significant contamination was obser ved in using a plaster mould.