Oil-Free Lubricants

In applying PS400 using the plasma spray-coating process, a 0.010 inch layer is deposited onto a metal surface. This composite coating often includes a metallic-based binder, a metal-bonded hardener, a high-temperature lubricant, and/or a low- temperature lubricant. PS400's improved metallic-based binder alloy greatly increases the structural strength and durability of the composite with respect to the operating temperature and the bearing load, and provides superior dimensional stability. PS400's metal-bonded oxide hardening agent provides additional hardness, wear resistance, and thermal stability, while also exhibiting a low coefficient of friction when used in sliding contacts. It is also significantly less expensive in terms of both acquisition and grinding processes. Depending on the desired environment, high- and low-temperature lubricants may be added to the composite coating. The preferred high-temperature lubricant is a metal fluoride and the optional optional low-temperature lubricant is composed of metals, such as silver or copper, that are soft enough to provide lubrication at low temperature while maintaining oxidation resistance with a sufficiently high melting point. These qualities permit the materials to be used over a broad temperature range. Once the spray coating has been applied, the metal surface is ground and polished to produce a smooth, self-lubricating surface before use. Unlike some coatings that must be diamond-ground, PS400 is readily ground with a substantially less expensive abrasive, such as silicon carbide. This grinding process generally yields a coating thickness of 200 to 400 micrometers. In instances when a coating is not convenient or possible, powder metallurgy techniques using PM400 can be used to make freestanding self-lubricating components such as bushings and wear plates. NASA's Glenn Research Center has developed high-temperature solid lubricant materials to reduce friction and wear in mechanical components, especially in extreme temperatures. The lubricant performs in temperatures from cryogenic levels to greater than 900°C. It has been formulated to provide higher density, smoother surface finish, and better dimensional stability than prior solid lubricant coatings. It can be applied either through plasma spraying as a coating, known as PS400, or as a solid composite material via powder metallurgy, known as PM400. Because of its ability to maintain thermal and chemical stability in higher temperatures, PS/PM400 enables efficiency increases of up to 40% in rotating machinery applications. Furthermore, PS/PM400 has proven durable in over 20,000 hours of turbine engine operation. PS/PM400 offers a substantial upgrade in wear resistance and efficiency for a vast range of aerospace and aeronautics applications. Its unique combination of good mechanical properties, long-term environmental durability, exceptional friction and wear-reducing characteristics, higher density, smoother finish, and better dimension stability establishes it in a class by itself among solid self-lubricating materials.