Low Friction Surfaces for Low Temperature Applications

Lunar and other extraterrestrial environments put extreme demands on moving mechanical components. Gears must continue to function and surfaces must continue to slide over a wide temperature range, the low end of which renders most conventional lubricants solidified while the high end vaporizes them, especially in a vacuum. Extremely long service lives are needed, and dust can cause abrasive damage. The solution is to use a high lubricity wear resistant solid, but not even all solid lubricants are suitable for the full range of challenges. We propose to use a novel electrocodeposition process to produce a quasicrystalline coating on the surface of metal parts. Quasicrystals are a unique family of alloys having symmetries found nowhere else. They are exceptionally hard, with low surface energies. Quasicrystalline coatings have been demonstrated to be stable over wide temperature ranges and to have low friction over the entire range. Our process produces solid, high-density, low friction coatings on a variety of metal substrates. The coatings are stable for the long periods needed to achieve long operating lives. They are applied under relatively mild conditions using readily available equipment and can be applied to substrates of any shape or size. In this project we will demonstrate the application of low friction coatings to gear alloys and show their low friction and wear properties over a temperature range that extends from above ambient to cryogenic.