Thick PVD Cermet and Graded DLC Coatings for Lubrication-Free Weapon Parts

The U.S. Army and small-arm weapon manufacturers are interested in surface finishes that are non-polluting and provide durable dry-lubrication, sliding-wear and sand-abrasion resistance, adhesion to weapon part materials, and corrosion protection in high-humidity environments. Engineered Coatings Inc. (ECI) along with Southwest Research Institute (SwRI) have demonstrated the capability to deposit thick, adherent, and dense corrosion-barrier nitride films by plasma enhanced magnetron sputtering in Phase I. On top of this thick PVD corrosion barrier, ECI and SwRI are depositing doped-diamondlike carbon (DLC) coatings by a novel non-line-of sight processing method (plasma ion immersion processing), which exhibits excellent adhesion and reduced coating defects. This bilayer architecture will offer surface lubricity, wear (sliding and abrasion) resistance, and corrosion protection. As a continuation of the Phase I program, we propose in Phase II to down-select to the 1 or 2 most promising bilayer coating combinations (e.g., thick nitride corrosion-barrier and doped DLC tribological coating) for additional optimization. This will include optimization of composition-grading profiles, higher fidelity tribological and corrosion screening tests, demonstration of coating reliability and reproducibility by multiple deposition runs, development of materials and process specifications, and coating demonstration on selected weapon parts for integration into assembled weapons for range firing tests.