Microstructure and Densification of Sintered (B+C)-Doped β-Silicon Carbide

Abstract

The role of boron and carbon during densification of sintered β-SiC was investigated through the combined approach of in-situ dilatometry and CTEM/AEM inspection of TEM-foils referring to well-defined densification events. Preliminary data obtained indicate that in the early stages of densification, boron is not enriched in the continuous carbon-rich surface layer covering the β-SiC powder particles nor does it segregate to internal interfaces in high quantities. Small boron quantities are dissolved in the SiC grains- Simultaneously with the β- to α- phase transformation, decomposition of foam-like B4C aggregates releases small B4C particles, which are bound intragranularly to α-SiC.

Grain‐Boundary Viscosity of Polycrystalline Silicon Carbides

“…TEM images of the overall microstructure of this latter material have been shown elsewhere. 10,11 In the undoped (HIPed) material, some small voids present at triple junctions were noted. Moreover, small graphite nests were observed even at low magnification (cf.…”

“…5. Braue et al 10 have recently discussed the role of boron and carbon during densification of sintered ␤-SiC by means of in situ dilatometry and microscopy/microanalysis characterization. They were able to explain the development of the final microstructure in the (B+C)-doped SiC and to relate it to each individual densification event.…”