Application of polypropylene carbonate for the tape casting of silicon nitride ceramics

QPAC40 (polypropylene carbonate), with a little decomposition residue, is commonly used as a binder in aluminum nitride (AlN) tape casting. In this paper, we tried to explore its application in silicon nitride (Si3N4) tape casting. By studying the influence of dispersant, binder, plasticizer/binder ratio, and solid loading on slurry and green tape properties, the optimum formulation of the tape casting of Si3N4 slurry was determined, and the green tape with a uniform structure and relative density up to 63.16% was prepared. Si3N4 ceramics were obtained by debinding at 600 degrees C for 1 h in vacuum and gas-pressure sintering at 1830 degrees C for 2 h in N-2. The thermal conductivity and flexural strength of Si3N4 ceramics were 56.28 +/- 1.21 W/(m center dot K) and 1130.67 +/- 23.58 MPa, respectively. These results indicated that QPAC40 can be used to prepare Si3N4 sheets through tape casting.