Materials/Lubricants and tribology
Lubricants and tribology
tribologyWhat this is
Lubricants, greases and bearing materials for moving parts.
In vacuum, normal oils boil away and clean metals can stick together. Dry lubricants and special greases are chosen for exactly this.
Types
Pick a type to see its materials.
| Type | Materials | Ranking |
|---|---|---|
| Dry lubricants | 3 | — |
| Liquid lubricants | none yet | — |
| Greases | none yet | — |
| Bearing materials | none yet | — |
What matters
The measurements we use to compare lubricants and tribology. Each one has a standard test and a direction: is higher or lower better?
| Measurement | Better when | How it is tested |
|---|---|---|
| Outgassing, total mass loss (TML)Mass lost in vacuum that can fog optics | lower | ASTM E595 |
| Outgassing, condensable (CVCM)Vapor that recondenses on cold surfaces | lower | ASTM E595 |
| Friction in vacuumHow easily surfaces slide in space | lower | Pin-on-disk in vacuum |
| Lubricant life, vacuum vs airHow much life ground handling uses up | higher | Pin-on-disk in vacuum and air |
| Galling and cold-welding tendencyWhether metals stick or seize in vacuum | lower | Vacuum adhesion and fretting tests |