Table 1.
Comparative properties of medical grades of Si3N4, ASTM35 grade 4 Ti, and PEEK
| Property | Units | Si3N4 | Ti-ASTM grade 4 | PEEK optima® |
|---|---|---|---|---|
| Composition | NA | Si3N4, Y2O3, AI2O3 | Chemically pure | Chemically pure |
| Surface composition | NA | SiNH2 and SiOH | TiO2 layer | –OH groups |
| Surface roughness (AFM) | nm | 10.1*, 25.3** | 3.06 | 1 |
| Isoelectric point | NA | 9 | ~4.5 | ~4.5 |
| Surface charge at pH = 7 | NA | Positive | Negative | Negative |
| Sessile water drop wetting angle | Degrees | 39 | 76 | 95 |
Notes:
*
Polished surface;
**
as-fired surface.