Densification of Binder Jet Silicon Carbide Ceramics through Polymer Infiltration and Pyrolysis of Preceramic Polymer

Author(s):

Emily Vanderploeg, Jaya Penn, Matthew Ivill, Jennifer Bennett, and Nicholas Ku

Abstract:

Ceramic materials, known for their high strength and hardness, are increasingly used in structural applications under high strain rates. However, the high hardness and intrinsic brittleness of ceramics limit the ability to machine structural parts with complex and intricate shapes using traditional manufacturing methods. When additive manufacturing techniques are used, particularly binder jetting, it is possible to fabricate geometrically complex ceramic components with materials such as silicon carbide (SiC). This study focuses on polymer infiltration and pyrolysis (PIP) as a net-shape densification process, leveraging a polycarbosilane polymer precursor, Starfire SMP-10, to infiltrate green bodies and densify them without inducing significant shrinkage. The goal is to attain a material density close to theoretical values without resorting to sintering. This study also involves the selection of suitable ceramic powders through powder analysis, considering factors such as flowability and tap density. Results indicate promising increases in density with double infiltration, although leakage of SMP-10 during heat treatments poses challenges. Scanning electron microscope imaging reveals nonuniform infiltration, particularly in the center of samples, potentially affecting densification. Despite these challenges, this study underscores the potential of PIP for densifying ceramic green bodies in binder jetting applications, albeit with the need for refinement in process parameters and precursor selection to mitigate leakage and achieve uniform densification.