Mechanisms of self-lubrication in patterned TiN coatings containing solid lubricant microreservoirs

✍ Scribed by Canan G. Guleryuz; James E. Krzanowski

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 840 KB
• Volume: 204
• Category: Article
• ISSN: 0257-8972
• DOI: 10.1016/j.surfcoat.2010.01.012

✦ Synopsis

The tribological mechanisms of friction and lubrication have been investigated in TiN coatings patterned to contain microscopic reservoirs for solid lubricant entrapment. Photo-lithography was used to fabricate three sets of samples on silicon wafers, varying the reservoir size (4 and 9 μm) and spacing (11 and 25 μm), which resulted in samples with a nominal reservoir area of either 2 or 10%. Pin-on-disk tests were run using lubricants of graphite and indium and counterfaces of alumina and steel (440C). In most cases, the samples with the 9 μm holes spaced 25 μm apart gave the lowest friction coefficients and longest wear life. Analysis of the wear tracks by SEM/EDS methods showed carbon to be present in the holes of the graphite/steel counterface samples, but TiO 2 was found in the holes of the graphite/alumina counterface samples. For the indium/steel counterface samples indium was detected within the microreservoirs, but iron was also found, transferred from the ball. These experiments highlight a variety of tribological mechanisms that can operate in microreservoir-patterned coatings.