Powder extrusion printing of silicon carbide ceramics: Optimization of water-soluble binder systems and sintering properties

A two-step debinding process, consisting of solvent debinding followed by thermal debinding has been demonstrated as an effective method for removing binders from green parts produced by powder extrusion printing. However, the organic solvents typically used in solvent debinding are often flammable, carcinogenic, and environmentally harmful. To address this issue, this study introduced a water-soluble binder system composed of polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), and ethyl vinyl acetate (EVA), specifically designed for fabricating silicon carbide (SiC) ceramic green parts via PEP. During water-based debinding, a large amount of PVA was removed, leaving micro-pores in the green part. These pores served as channels for the remaining binder to escape during thermal debinding. Subsequent processing involving phenolic resin impregnation and pyrolysis (PRIP), followed by liquid silicon infiltration (LSI), resulted in Si/SiC ceramics with a density of 2.83 +/- 0.09 g/cm3 and a strength of 279.5 +/- 8.4 MPa.