Piston ring materials will require higher temperature strength properties such as Hll tool steel or 422 stainless steel.

The coating systems will be screened for wear and friction at 350 °C under lubricated conditions. Coatings which show promise of meeting the wear and friction goals will be optimized by adjustments to chemistry and hard particle content to meet the wear and friction goals. Optimized coating systems will be fully characterized for oxidation, adherence, uniformity, thermal shock, wear and friction - see Figure 2.

Each of the optimized coatings will be tested for wear and friction using a pin-on-disk type of test. The specimens are shown in Figure 3. The coatings will be applied to the disk and the pin will be made from silicon nitride, silicon carbide, alumina, or zirconia. Tests will be run at 350 °C under lubricated conditions. The lubricant will be either Stauffer E-85056 or Mobil Jet Oil 254. The lubricant selected will depend upon the expected compatibility of the lubricant and coating. Characterization of these

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