Aluminium Oxide (Alumina) 99.5% vs Silicon Nitride: 2% composition overlap. Significantly different materials serving different application areas.
Aluminium Oxide (Alumina) 99.5% vs Silicon Nitride
Side-by-side chemical composition and mechanical property comparison.
Overview
Aluminium Oxide (Alumina) 99.5%
The most widely used engineering ceramic. Alpha-phase alumina (99.5% Al2O3) offers exceptional hardness (1440 HV), excellent dielectric properties, high compressive strength (2600 MPa), good thermal conductivity (35 W/m·K), and outstanding chemical resistance. Usable to 1750°C. Applications include wear pads, seal rings, substrates, thread guides, grinding media, furnace tubes, ballistic armor, and high-voltage insulators. Available in purities from 94% to 99.8%.
Silicon Nitride
High-performance non-oxide ceramic with the highest fracture toughness among engineering ceramics (6–8 MPa·m½). Interlocking rod-like β-Si3N4 microstructure provides excellent thermal shock resistance. Flexural strength 690–830 MPa, density 3.27–3.29 g/cm³ (lightweight), thermal conductivity 29–30 W/m·K. Hardness 1450–1580 HV. Applications: precision bearing balls and rollers, cutting tools, turbocharger rotors, engine valves, metal forming dies, weld positioners.
| Aluminium Oxide (Alumina) 99.5% | Silicon Nitride | |
|---|---|---|
| Material Number | — | — |
| Category | ceramic | ceramic |
| Standard | — | — |
Chemical composition (wt%)
| Element | Aluminium Oxide (Alumina) 99.5% | Silicon Nitride | Overlap |
|---|---|---|---|
| Al2O3 | ≥ 99.5% | 1–5% | No overlap |
| SiO2 | ≤ 0.2% | — | — |
| MgO | ≤ 0.1% | ≤ 3% | OK |
| Na2O | ≤ 0.1% | — | — |
Mechanical properties
| Property | Aluminium Oxide (Alumina) 99.5% | Silicon Nitride | Unit |
|---|---|---|---|
| density | ≥ 3.89 | ≥ 3.29 | g/cm3 |
| flexural_strength | ≥ 379 | ≥ 830 | MPa |
| compressive_strength | ≥ 2600 | — | MPa |
Compatibility Assessment
Aluminium Oxide (Alumina) 99.5% and Silicon Nitride have significantly different compositions (2% overlap). These materials are not interchangeable and serve different application areas.
Automated assessment based on composition analysis
Frequently Asked Questions
Is Aluminium Oxide (Alumina) 99.5% the same as Silicon Nitride?
Aluminium Oxide (Alumina) 99.5% and Silicon Nitride have a 2% composition overlap. They are generally not directly interchangeable.
Can I replace Aluminium Oxide (Alumina) 99.5% with Silicon Nitride?
Generally not recommended. The compositions differ significantly (2% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between Aluminium Oxide (Alumina) 99.5% and Silicon Nitride?
The main differences are in the following elements: Al2O3. Aluminium Oxide (Alumina) 99.5% is a ceramic grade, while Silicon Nitride is a ceramic grade.
View full data for each material:
Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.