Physics / mechanism
Ceramics are inorganic, non-metallic solids bonded via ionic or covalent lattices, giving extreme hardness (Al₂O₃ ~15–20 GPa Vickers), thermal stability (SiC service temps >1600 °C), and low thermal expansion (AlN CTE ~4.5 ppm/°C vs. copper’s 17). Composites—ceramic matrix composites (CMCs) in particular—embed fibres (SiC/SiC, C/SiC) to suppress catastrophic brittle fracture, achieving fracture toughness 15–25 MPa·m½ vs. monolithic ceramic’s 3–5. Key process routes: chemical vapour infiltration, hot-press sintering, reactive melt infiltration. State of art: SiC/SiC CMCs in GE LEAP turbine blades running at 1315 °C without thermal barrier coatings; AlN substrates at 170–200 W/m·K dominating power module packaging; ultra-low-loss AlN waveguides for integrated photonics below 0.5 dB/cm.
Competitive landscape
Primary competition comes from superalloys (Ni-based, Inconel) in thermal applications—better toughness, worse temp ceiling and weight; polymers/CFRP in structural composites—far lighter but temperature-limited to ~300 °C. In substrate/packaging: AlSiC, copper-moly, and organic laminates compete on cost but lose on thermal conductivity and CTE match at high power density. In photonics, SiN and LiNbO₃ compete with AlN on waveguide platforms.
| Material | Thermal conductivity | Max temp | Cost |
|---|---|---|---|
| SiC/SiC CMC | 20–40 W/m·K | 1600 °C | Very high |
| Ni superalloy | 11–13 W/m·K | 1100 °C | High |
| AlN substrate | 170–200 W/m·K | 800 °C | Moderate |
Companies using
Connected ideas
Sources
Frontier (open questions)
- To be added.