United States of America as Represented by the Secretary of the Air Force

Lewis Rosado

Nelson H Forster

Christopher J Klenke

James P King

Rabi S Bhattacharya

Amarendra K Rai

Hitesh K Trivedi

Wei T Shih

The present invention provides a method for applying a tribological coating to a carbon composite substrate. The method includes providing the carbon composite substrate, depositing a layer of carbon on the substrate, applying a layer of aluminum on the layer of carbon, annealing the substrate at a temperature greater than a melting temperature of aluminum, and applying a layer of silver. A layer of mixed aluminum and silver may be substituted for the layer of silver.

Metal coatings for reduced friction in composites

Provided is a method to produce high-temperature lubricious glassy films on silicon-based ceramics. The method comprises the steps of (a) oxidizing a silicon-based component, (b) coating the oxidized component with an alkali metal compound, and (c) heating the component to a high temperature in a sulfur-rich oxidizing environment. The steady state sliding friction coefficient values obtained with this system in 600&deg; C. air are similar to those obtained with liquid lubricants operating under boundary lubrication conditions at much lower temperatures.

Method for producing high-temperature lubricious glassy films on silicon-based ceramics

A novel rolling element bearing assembly comprises an inner race, an outer race, a plurality of rolling elements, and a carbon-carbon composite retainer. The carbon-carbon composite retainer is fabricated by providing a woven tube, cutting the woven tube into suitably sized rings, piercing the rings for rolling bearing elements, and densifying the resulting retainer. Alternatively, the tube can be densified, then cut into a plurality of retainer blanks which are then pierced. For use at operating temperatures above about 650.degree. C., ceramic coatings, such as silicon carbide (SiC), silicon nitride (Si.sub.3 N.sub.4) and boron nitride (BN) can be used to provide oxidation resistance for the carbon-carbon composite retainer at such elevated temperatures.

High temperature rolling element bearing

A method for lubricating a ceramic bearing surface which comprises applying a cesium-containing compound selected from the group consisting of Cs.sub.2 MoO.sub.4, Cs.sub.2 SO.sub.4, Cs.sub.2 WO.sub.4, Cs.sub.2 WOS.sub.3, Cs.sub.2 MoOS.sub.3 and CsOH, to the bearing surface and heating the thus-coated bearing surface to a temperature of about 300.degree. C. or greater. Alternatively, the cesium-containing compound may be applied in admixture with a lower alkali metal silicate. This method is particularly useful for lubricating the bearings in expendable, high temperature turbine engines, such as those used in expendable missiles.

High temperature cesium-containing solid lubricant

System and method for high temperature lubrication of a bearing surface of a movable machine part using lubricant sublimation is described which comprises a source of solid lubricant, a heater disposed in thermal contact with the lubricant for heating the lubricant to sublimation and a conduit for conducting sublimated lubricant vapors into contact with the bearing surface to be lubricated.

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Centerville, OH, United States of America

Lewis Rosado