Novel In-Cylinder Wear Coatings for Improved High Output Military Diesel Engine Performance and Durability

Future U.S. Army vehicles will require engines with low heat rejection, high power density, lower-friction (15 % reduction), reduced fuel consumption (2-5% lower), and higher durability. Our team, NanoCoatings, Inc. (NCI) and Southwest Research Institute (SwRI), will down-select the most promising coating technologies and coating materials for both piston-rings and cylinder-liners. Our preliminary down-selection consists of a high TRL 7 PVD coating already demonstrated by SwRI in heavy-duty diesel engine testing, which will reduce development risks to the U.S. Army. NanoCoatings, Inc. has a similar deposition system to enable technology transfer of the SwRI coating. For the cylinder liners, NCI proposes a higher risk novel Plasma Electrolytic Deposition (PED) immersion coating technology to deposit stabilized zirconia with WS2 solid-lubricant nanoparticles. NanoCoatings has already demonstrated PED coating of steels with alumina and the PEO coversion of Zr-metal into zirconia. Consequently we have relevant experience with this approach to produce a low thermal-conductivity, thermal-barrier coating containing solid-lubricants on cast-Fe liner material. Coatings will be characterized using SEM examinations for microstructure/composition, indentations for relative adhesion/toughness, nanoindentation for hardness and modulus, block-on-ring sliding wear tests and PLINT TE77 sliding wear tests of coated ring segments against liner segments in diesel engine lubricants.