Nano-Multilayered Dry-Machining Coating for High-Temperature Solid-Lubrication of Aircraft Engine-Control Components

The U.S. Air Force seeks a solution to wide-temperature-range lubrication that offers reliable performance and offers long-life durability. High-mach gas turbine engines will require bearings to operate up to 650C at loads up to 12.46 kN. Fluid lubricants are limited under these extreme conditions. Engineered Coatings, Inc. and Southwest Research Institute propose to enhance a nanostructured / nanolayered solid-lubricant coating, which has shown exceptionally low-friction (<0.1), low-wear, and non-reaction tendency from 25 to 1000C under dry-machining trials. As part of our enhancement effort, we propose to add silicon (Si) by introduction of a gas precursor during enhanced-plasma deposition from metal targets in a nitrogen/argon working gas. Silicon additions have also been shown to be beneficial from formation of hydroxide compounds. Screening high-temperature wear tests will be conducted along with surface analysis of wear tracks to establish the compounds responsible for the low-friction behavior as a function of test temperature. BENEFIT: For military applications, the coating technology will be applied to anti-wear and low friction coatings for bearings in high-mach gas turbine engines. Weapon systems with mechanical assemblies that operate under elevated temperatures can also benefit from this coating development. Commercial systems that will benefit from the development of a wide-temperature range solid lubricant for bearings include gas-turbine engines used commercial aircraft, power generators, and metallurgical processes, such as hot profile rolling and hot forming operations.