Fabrication and tribological properties of hard thin films with solid lubricant microreservoirs

Hard coatings containing micron-sized reservoirs have been fabricated and investigated to evaluate their tribological properties. These composite coatings have the potential to reduce friction and extend the life of wear surfaces through the use of a structural matrix embedded with microreservoirs containing solid lubricants. In this thesis, methods of using polymer or silica microspheres as templates for reservoirs in wear resistant coatings were examined. Magnetron rf-sputtered TiN and TiCN films and magnetron rf reactively sputtered TiN films were investigated for use as hard films containing these microreservoirs. The reservoir size as a function of microsphere size and film thickness was measured. Wear tests of the microreservoir thin films with MoS2 and graphite lubricants have been used to examine the performance of the coatings and determine the optimum microreservoir percentage. The coatings with microreservoirs and lubricant showed friction reduction compared to similar coatings without microreservoirs. The maximum coverage achieved using direct spray techniques was about 12 percent. Increased levels of microreservoir coverage percent showed increased levels of friction reduction, with 28% friction reduction at maximum coverage.