Single-step wick-debinding and sintering for powder injection molding

We have investigated the possibility of merging the wick-debinding and sintering of injection-molded ceramic parts into a single-step operation. The basic idea is to use an embedment that serves as a wicking agent in the first stage of the procedure, but then burns out completely when the temperature exceeds approximately 500 °C, leaving the samples free of any organic binder or contamination so that they are ready for sintering. Carbon black was used as the wicking agent for two reasons. First, it has great wicking-agent properties, due to its high porosity with a small pore size, while exhibiting good wetting with the molten paraffin binder. Second, it burns in air at high temperature, at which point the wick-debinding has already been completed. The whole process from molded parts to fully sintered parts can be completed in a single furnace. Besides making the process shorter, the tedious and delicate operations of cleaning and transporting the fragile debinded parts after wick-debinding are avoided.