A new process for creating a solid‐phase sintered body using a unique densification process between powders

• Published in: International journal of ceramic engineering & science 2021-05, Vol.3 (3), p.113-119
• Main Authors: Ishikawa, Toshihiro, Naito, Makio
• Format: Article
• Language: English
• Subjects: Aluminum; Amorphous silicon; Carbon; Conversion; Densification; Gas flow; Heat; Interstices; Nitrogen; Plasma sintering; Polycrystals; Polymers; Reduction; SiC powder; SiC‐polycrystalline fiber; Silicon carbide; Silicon dioxide; Sintering (powder metallurgy); Sintering aids; solid‐phase sintering
• ISSN: 2578-3270; 2578-3270
• DOI: 10.1002/ces2.10082

SiC‐polycrystalline fiber (Tyranno SA) had been developed using a conversion process from amorphous Si‐Al‐C‐O fiber to SiC‐polycrystalline fiber via carbothermal reduction (~1700°C) and sintering processes (~2000°C). In the conversion process, the carbothermal reduction (SiO + 2C → SiC + CO and SiO2 + 3C → SiC + 2CO) of the oxide phase and residual carbon contained in the raw Si‐Al‐C‐O fiber and the subsequent sintering proceed inside each filament. Here, we describe a new densification process of SiC powder that optimally uses the conversion process from Si‐Al‐C‐O fiber to SiC‐polycrystalline fiber. In this new process, we adopted the densification process, that occurred in each filament of the Si‐Al‐C‐O fiber, for the development of a dense SiC sintered body using partially oxidized SiC‐powder with surface oxide layer and polymer‐derived pyro‐carbon containing a considerable quantity of aluminum as sintering aid for SiC crystals. Herein, the reactions and sintering, which occurred in each filament of Si‐Al‐C‐O fiber, proceeded in the interstices of SiC powder to create a dense SiC body. In this paper, we will describe the new densification system of SiC powder. Pyro‐carbon existing on the pre‐oxidized SiC powder.