SiC-Si composite part fabrication via SiC powder binder jetting additive manufacturing and molten-Si infiltration

Abstract

Abstract High hardness and superior thermal stability of silicon carbide (SiC) are advantageous for engineering parts but they make it difficult to manufacture complex products with full density. Reaction-bonded SiC are effective solutions for the paradox. SiC-Silicon (Si) composite materials are manufactured by molten Si infiltration through porous SiC and/or Carbon (C) preforms owing to superior wetting of molten Si on SiC and reactive wetting of molten Si on C. Cold isostatic pressing of mixed powders feedstock, green machining and joining are a typical manufacturing pathway for green-body parts. Multiple processes with tools and significant materials loss are regarded as wastes from the viewpoint of lean manufacturing principle. In the present study, feasibility of binder jetting additive manufacturing (BJT AM) technology was assessed for green-body part manufacturing stage in the course of SiC/Si parts production. Adoption of BJT AM showed opportunities for process savings, tool savings, materials savings and design freedom. However, strength of brown-body parts as well as density of as-built green-body parts are challenges. To overcome the limitations, phenolic resin solution impregnation through as-built green parts was introduced. It is highlighted that green-body strength, brown-body strength and infiltrated-body strength are modified with evolutionary phase transformations from cured phenolic resin to reaction-synthesized SiC by way of decomposed carbon through the conventional post-AM densification manufacturing pathway.