Role of organic additives on non-aqueous tape casting of SiAlON ceramics

Abstract

Suspensions consisting of precursor alpha/beta SiAlON forming powders azeotropic solvent mixture of 60 MEK/40E dispersant binder, and plasticizer were optimized for tape casting by theological measurements and tape properties Sodium tripolyphosphate (STPP) was introduced as a dispersant for low temperature applications of alpha/beta SiAlONs Optimum STPP amount was determined as 0 012 g/m(2) (of the particle surface) for stable alpha/beta SiAlON suspensions Different amounts of binder/plasticizer mixtures were added to the slurries and the effects on theological and green tape properties were investigated Green tapes with dibutyl phthalate (DBP), and plasticizer mixture, poly(ethylene glycol) (PEG) and DBP, exhibited centered cracks with high plasticity, on the other hand, polyvinyl butral (PVB) and PEG showed no crack but low plasticity Therefore, many different parameters were found to be effective on final tape properties In addition, tapes were prepared with 6 vol% PVB + PEG, sintered at 1800 degrees C for 2 h and exhibited almost 97%TD in room temperature applications of alpha/beta SiAlONs (C) 2010 Elsevier Ltd All rights reserved