BAE Systems produces two grades of Sintered/HIPed Silicon Nitride (Si3N4) for high performance wear applications in which no micro-porosity is permissible. These materials have an exceptional combination of high toughness and hardness that makes them excellent for bearing and other wear applications. BAE Systems produces these materials in sizes up to 2 1/4" balls.
The chart below lists typical properties.
| Grade of Sintered/HIPed Si3N4 | PSX-H | PSO-H1 | |
| Bulk Density | g/cm^3 | 3.28 | 3.28 |
| Flexural Strength, | Ksi | 113 | 110 |
| (4-Pt MOR) @RT | MPa | 780 | 760 |
| Characteristic Strength | MPa | 825 | 805 |
| Weibull Modulus (m) | 14 | 16 | |
| Elastic Modulus (E) | GPa | 300 | 275 |
| Poisson's Ratio (v) | 0.27 | 0.24 | |
| Hardness (Vickers 5.0 kg) | kg/mm^2 | 1510 | 1600 |
| Fracture Toughness (Chevron Notch) | MPa-m^1/2 | 5.9 | 6.5 |
| Thermal Expansion (RT-1000°C) | 10^-6/°C | 3.3 | 3.3 |
| Thermal Conductivity @RT | (W/m-K) | 30 | 20 |
| Electrical Resistivity |
Ω-cm |
>10^14 | >10^14 |
