Material Guide
Ceramic Properties
Technical ceramics offer extreme hardness, wear resistance, and high-temperature capability. Learn about alumina, zirconia, and silicon carbide for industrial applications.
4 min readUpdated July 2026
Overview
Technical ceramics (alumina, zirconia, silicon carbide) are used in industry for their extreme hardness, wear resistance, and high-temperature capability. They are used in pump seals, valve trim, bearings, and wear-resistant liners.
Common Technical Ceramics
| Type | Key property | Max temp (°C) | Typical use |
|---|---|---|---|
| Alumina (Al₂O₃) | Hard, wear-resistant, cheap | 1500 | Seal faces, insulators, liners |
| Zirconia (ZrO₂) | High toughness for ceramic | 1000 | Bearings, valve trim, cutting tools |
| Silicon Carbide (SiC) | Extreme hardness + thermal cond. | 1600 | Seal faces, nozzles, heat exchangers |
| Silicon Nitride (Si₃N₄) | Thermal shock resistant | 1200 | Bearings, turbine components |
Key Properties (Alumina)
| Property | Value |
|---|---|
| Density | 3900 kg/m³ |
| Hardness | 1800 HV (9 Mohs) |
| Compressive strength | 2000–3000 MPa |
| Tensile strength | 200–300 MPa |
| Max service temperature | 1500°C |
| Thermal conductivity | 30 W/m·K |
Advantages
- Extreme hardness: 9 on Mohs scale — only diamond is harder. Resists abrasion and erosion.
- Excellent wear resistance: Lasts 10–100× longer than steel in abrasive service — used in pump seals and valve trim.
- High temperature capability: Maintains strength at temperatures where metals soften or melt.
- Chemical inertness: Resists most acids, alkalis, and corrosive environments.
- Electrical insulation: Excellent insulator — used in spark plugs and sensor bodies.
Limitations
- Brittle: The Achilles heel of ceramics — they fail by fracture, not yielding. Cannot absorb impact or shock.
- Poor thermal shock resistance: Rapid temperature changes cause cracking due to low thermal expansion mismatch.
- Difficult to machine: Cannot be machined after firing — must be ground with diamond tools. Final shape must be cast.
- No ductility: Zero plastic deformation — no yielding before failure.
Typical Applications
- Mechanical seal faces (pumps, mixers)
- Valve seats and balls (abrasive service)
- Ceramic bearings (high-speed, high-temp)
- Wear tiles and liners (chutes, hoppers)
- Cutting tools (turning, milling)
- Insulators (spark plugs, sensors)
- Heat exchanger tubes (SiC)
Chemical Compatibility
| Chemical | Rating |
|---|---|
| Acids (most) | Excellent |
| Alkalis | Excellent |
| Molten metals | Good (most) |
| Steam | Excellent |
| Abrasive slurries | Excellent |
How CHI can help
Ask CHI about ceramic materials and to recommend them for wear-resistant or high-temperature sealing applications. The CHI assistant can recommend the right material for your specific application, explain chemical compatibility, and flag when a material is unsuitable for your operating temperature or environment.