Related Experiment Video
Updated: Oct 12, 2025
13:58
Probing C84-embedded Si Substrate Using Scanning Probe Microscopy and Molecular Dynamics
Published on: September 28, 2016
11.9K
Microstructural Analysis of Novel Preceramic Paper-Derived SiCf/SiC Composites
Ke Li1,2, Egor Kashkarov2, Hailiang Ma1
1China Institute of Atomic Energy, Beijing 102413, China.
Materials (Basel, Switzerland)
|November 27, 2021
Summary
This study reveals how spark plasma sintering affects silicon carbide fiber/silicon carbide (SiCf/SiC) composites. Longer sintering times and higher temperatures promote the 6H-SiC phase and create silicon vacancies.
Area of Science:
- Materials Science
- Ceramic Engineering
- Nanotechnology
Background:
- Silicon carbide fiber/silicon carbide (SiCf/SiC) composites are advanced materials with excellent high-temperature properties.
- Fabrication methods like spark plasma sintering (SPS) are crucial for optimizing their microstructure and performance.
- Understanding the phase evolution and defect formation during sintering is key to tailoring composite properties.
Purpose of the Study:
- To investigate the microstructural evolution of preceramic paper-derived SiCf/SiC composites fabricated via spark plasma sintering.
- To analyze the effects of sintering temperature, time, and pressure on phase composition and defect formation.
- To characterize the changes in SiC polytypes and the presence of carbon species within the composite structure.
Main Methods:
- Spark plasma sintering (SPS) was used to fabricate SiCf/SiC composites with approximately 10 wt% fiber content.
- Microstructural analysis was performed using positron annihilation methods, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy.
- Sintering parameters varied, including temperatures of 2100/2200 °C and pressures of 60/100 MPa, with extended sintering times explored.
Main Results:
- Increased sintering time led to a significant rise in the 6H-SiC phase proportion, reaching approximately 80%.
- Elevating the sintering temperature from 2100 °C to 2200 °C induced a partial transition from 4H-SiC to 6H-SiC.
- Positron annihilation spectroscopy indicated the formation of silicon vacancies, evidenced by a long-life positron component.
- Raman spectroscopy revealed characteristic peaks of turbostratic graphite, attributed to carbon diffusion from SiC fibers and preceramic paper during high-temperature sintering.
Conclusions:
- Spark plasma sintering parameters critically influence the phase composition and defect structure of SiCf/SiC composites.
- The formation of Si vacancies and the presence of graphite indicate complex interfacial reactions and mass transport during high-temperature processing.
- The study provides insights into controlling the microstructure of SiCf/SiC composites for enhanced material properties.
