High-Compressive-Strength Silicon Carbide Ceramics with Enhanced Mechanical Performance

Area of Science:

• Materials Science
• Ceramic Engineering
• Nanotechnology

Background:

• Reaction-bonded silicon carbide (RBSC) is crucial for high-stress applications.
• Conventional RBSC often faces limitations in mechanical performance.
• Optimizing fabrication processes is key to enhancing RBSC properties.

Purpose of the Study:

• To fabricate high-performance RBSC ceramics via an optimized liquid silicon infiltration (LSI) process.
• To investigate the impact of multi-modal SiC particle gradation and nano-carbon additives on RBSC properties.
• To establish a scalable strategy for RBSC design for extreme mechanical environments.

Main Methods:

• Employed liquid silicon infiltration (LSI) with multi-modal SiC particle gradation.
• Incorporated nano-carbon black (0.6 µm) additives.
• Engineered porous preforms with hierarchical SiC distributions and tailored carbon sources.
• Conducted microstructural analyses to understand mechanical enhancement mechanisms.

Main Results:

• Achieved compressive strength of 2393 MPa and flexural strength of 380 MPa.
• Demonstrated homogeneous β-SiC formation and effective crack deflection.
• Ultrafine SiC particles (0.5-2 µm) refined pore architecture and improved silicon infiltration.
• Observed a 23% increase in compressive strength with ultrafine SiC compared to coarse-grained systems.

Conclusions:

• The optimized LSI process with hierarchical SiC and nano-carbon additives yields superior RBSC ceramics.
• Microstructural control, particularly with ultrafine SiC particles, enhances mechanical properties and load transfer.
• This work provides a scalable method for producing RBSC for high-stress structural components.