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

TL;DR

This paper shows how to make stronger silicon carbide ceramics using a new fabrication process for better mechanical performance.

Contribution

A scalable fabrication method for high-strength silicon carbide ceramics using optimized particle gradation and additives is introduced.

Findings

The ceramics achieved compressive and flexural strengths of 2393 MPa and 380 MPa, respectively.

Ultrafine SiC particles improved compressive strength by 23% compared to coarse-grained systems.

Homogeneous β-SiC formation and crack deflection mechanisms enhanced mechanical properties.

Abstract

This study demonstrates the successful fabrication of high-performance reaction-bonded silicon carbide (RBSC) ceramics through an optimized liquid silicon infiltration (LSI) process employing multi-modal SiC particle gradation and nano-carbon black (0.6 µm) additives. By engineering porous preforms with hierarchical SiC distributions and tailored carbon sources, the resulting ceramics achieved a compressive strength of 2393 MPa and a flexural strength of 380 MPa, surpassing conventional RBSC systems. Microstructural analyses revealed homogeneous β-SiC formation and crack deflection mechanisms as key contributors to mechanical enhancement. Ultrafine SiC particles (0.5–2 µm) refined pore architectures and mediated capillary dynamics during infiltration, enabling nanoscale dispersion of residual silicon phases and minimizing interfacial defects. Compared to coarse-grained counterparts, the ultrafine SiC system exhibited a 23% increase in compressive strength, attributed to reduced sintering defects and enhanced load transfer efficiency. This work establishes a scalable strategy for designing RBSC ceramics for extreme mechanical environments, bridging material innovation with applications in high-stress structural components.

Figures