Material Overview
Silicon nitride (Si₃N₄) is a high-performance structural ceramic renowned for its exceptional thermal stability, mechanical strength, and wear resistance. Composed of covalently bonded silicon and nitrogen atoms, it combines low thermal expansion (3.0~3.2 × 10⁻⁶/K) with high fracture toughness (6~7 MPa√m), making it ideal for aerospace, automotive, and biomedical applications. Its unique microstructure—long β-phase grains embedded in a fine-grained matrix—enhances crack deflection and load-bearing capacity.|
Silicon Nitride Vs Aluminum Nitride Data Table
| Property | Aluminum Nitride | Silicon Nitride |
| Density (g/cm³) | 3.3 | >3. 2 |
| Flexural Strength (MPa) | >310 | >700 |
| Modulus of Elasticity (GPa) | 310 | 290-310 |
| Thermal Conductivity (W/m·K) | 170–230 | 20 |
| Max. service temperature (℃) | 1200 | 1400 |
| Dielectric Strength (kV/mm) | >17 | 13 |
Silicon nitride is a material with a relatively low thermal expansion coefficient among industrial ceramics, which means it has good thermal shock resistance. Silicon nitride has excellent fracture resistance, high temperature resistance, and good oxidation resistance, which makes it suitable for use under high temperature and high load conditions.The silicon nitride material products we provide are mainly silicon nitride substrates, silicon nitride plates, silicon nitride tubes and silicon nitride structural ceramic parts.
Key Properties
- Thermal Performance: Withstands temperatures up to 1,400°C without deformation or oxidation.
- Mechanical Strength: Compressive strength exceeding 2,500 MPa, surpassing most metals and ceramics.
- Chemical Inertness: Resists acids, alkalis, and molten metals, ensuring longevity in corrosive environments.
- Biocompatibility: Non-toxic and osteointegrative, approved for dental implants and orthopedic devices.
Applications
- Industrial: Hybrid ceramic bearings (30–50% higher speed than steel), turbocharger rotors, rocket thrusters.
- Medical: Precision parts for related medical equipment.
- Automotive: Diesel engine preheating plugs (3–5 sec to 1,000°C, lifespan 15,000 hours).
Processing Techniques
- Dry Pressing : Enhances density (≥99%) for high-stress components.
- Injection Molding: Suitable for small, complex and precision parts (such as gears, cutting tools).
- Tape Casting: Suitable for thin sheet materials (such as ceramic substrates).
- CNC Machining: Achieves precision tolerances (±0.01 mm) for medical devices.
Silicon nitride bearings outperform steel in extreme conditions due to their low density (3.2 g/cm³) and high hardness (1,420 HV). The material’s thermal stability minimizes friction-induced heat, enabling 30–50% higher rotational speeds in aerospace turbines and industrial machinery. Additionally, its non-conductive properties prevent electrical arcing in hybrid electric vehicles. Studies show a 10x lifespan improvement over steel in high-vibration environments, reducing maintenance costs by 40%.
Silicon nitride turbocharger rotors operate efficiently at 1,400°C, leveraging low thermal expansion to maintain dimensional stability under rapid temperature changes. This reduces “turbo lag” by 15% compared to metal alloys. In diesel engines, Si₃N₄ preheating plugs reach 1,000°C in 3–5 seconds, ensuring reliable cold starts at -30°C. The material’s resistance to thermal shock also extends component life in rocket thrusters exposed to cyclic heating.
Silicon nitride substrates can replace aluminum substrates, especially for high-power, high-temperature or insulation-required applications (such as IGBT modules) because of their good thermal conductivity, thermal matching with chips and high temperature resistance. However, aluminum substrates are cheaper and suitable for general heat dissipation scenarios. If you need to balance performance and cost, you can consider using silicon nitride locally or choosing a copper substrate.