Gas turbine engine oil additives for advanced bearings - advanced steels

In order to meet new requirements for improved performance and longer life, engine manufacturers have investigated the use of new, advanced high-chrome steels for incorporation into new gas turbine engines used in military aircraft. These advanced steelsallow higher operating temperatures and higher speed capabilities, and provide improved corrosion and fatigue resistance. However, in performance tests conducted to date, bearings made of these new high-chrome materials have experienced significantlyshorter life than anticipated. Existing lubricants have been specifically formulated with aryl phosphate antiwear additives that provide excellent performance under elastohydrodynamic and boundary lubrication conditions when used in conjunction with thecurrent low chrome-containing bearings based on conventional steels. Under these conditions the aryl phosphate additives breakdown to form a lubricious film at the rubbing metal surface contact points, and prevent excessive wear of the bearings.Apparently, the chemistry of the new high-chrome steels does not interact in the same way with the aryl phosphate additives to form the life extending lubricious films. Under the current SBIR solicitation, the U.S. Air Force is interested in the research,formulation and development of new and effective lubricity additives for high temperature gas turbine engine oils (GTOs) to enhance the performance of bearings using the new high-chrome steels. METSS proposes to develop new antiwear additives for GTOs forspecific use with the new high-chrome steel bearings, using a proven approach to cost-effective materials development. METSS will draw on existing materials and technology, working directly with industry participants to select the best materials forproduct formulation, and evaluate the new GTOs under a stringent testing and evaluation program to select the best performers. This approach ensures a non-biased approach to achieving the program objectives and opens up the opportunity of creatingcustomized formulations that can be designed to directly address performance requirements using commercial-off-the-shelf enhanced GTO formulation components. The development of successful, new antiwear lubricant additives for advanced steel bearings willhave both military and commercial uses. For example, many municipalities use power generation turbines, which have similar issues to aircraft gas turbine engines. Another commercial application is for commercial aircraft because commercial aircraftengine advancements usually follow military advancements by about five years.