Gear Coatings for Loss of Lubrication Mitigation

Army rotorcrafts are required to operate in extreme situations such as loss of lubrication to the drive systems. Current designs allow for 30 minutes of operation at 50% power, but the Army has a need to improve aircraft survivability beyond this threshold. Phygen Coatings has developed a unique, patented technology for surface improvement of industrial tooling and precision machine components. In this project, we propose to demonstrate the feasibility of using this commercially-proven technology to reduce friction and wear on aircraft gears under dry conditions. This solution will ultimately enable aircraft transmissions to operate without lubrication at elevated temperatures for over 45 minutes at a specified 50% power rating. With Phygens accelerated arc plasma deposition process, the coating will be more highly adherent, dense, and wear resistant than common coatings from sputtering or arc systems. The coating architecture will begin with a base layer of chromium nitride, which will be followed by lubricious layers of silicon carbide and diamond-like carbon to reduce friction and wear under a loss of lubrication condition. Dual-layer coatings of CrN/SiC and CrN/DLC have already proven they can provide low friction, high wear resistance, and excellent adhesion in tribological tests performed at the Armys Benet Labs.