A review is given of the selection and tribological testing of materials for high-temperature bearings and seals. The goal is to achieve good tribological properties over a wide range of temperatures, because bearings and seals must be functional from low-temperature start-up conditions on up to the maximum temperatures encountered during engine operation. Plasma-sprayed composite coatings with favorable tribological properties from 25 to 900°C are discussed. The performance of these coatings in simple tribological bench tests is described. Examples are also given of their performance in high-speed sliding contact seals, as Stirling cylinder liner materials, and as backup lubricants for compliant foil gas bearings.
Some Composite Bearing and Seal Materials for Gas Turbine Applications—A Review