MEASUREMENT OF ELONGATIONAL FLOWS IN CERAMIC PROCESSING - REVIEW

Novel manufacturing processes for ceramics which rely on extensional s trains that can be sustained by a crowned suspension include fibre spi nning, foam manufacture, vacuum forming, blow moulding and film blowin g. In the selection of powders, powder volume fractions and organic ve hicles for these processes, elongational flow measurements are preferr ed because shear pow tests frequently no not pr edict elongational flo w behaviour. The main techniques that have been used for uniaxial and biaxial characterisation of polymers and filled polymers ann which are capable of being applied to ceramic systems are reviewed. Melt streng th provides a limitation on extension and the various criteria for mel t fracture are discussed. (C) 1997 Elsevier Science Limited.