Laser Surface Processing of “Chameleon” Coatings for Aerospace Tribology

Adaptive solid lubricants were developed to provide friction and wear reduction in aerospace environments such as ambient humid air, vacuum, or dry nitrogen (storage and on ground testing). Achieving high durability and long life requires solid lubricant reservoirs near the tribological surface. Reservoirs were fabricated using precision laser processing to generate arrays of micrometer-sized holes with well-controlled size, location, and density on the surface of hard ceramic coatings applied to steel substrates. Solid lubricants based on dichalocogenides and carbon were applied by burnishing and sputtering to the laser treated surfaces. Sliding friction tests were performed against steel balls in environments with different humidity. The result indicates that there is an optimum reservoir surface density, where the life of the solid lubricant is improved by an order of magnitude. The laser-processed reservoirs enable coating operation in variable environments.