Laser surface texturing has been successfully applied in the past to various machine\nelements in order to improve their tribological performance. In this study, direct laser interference\npatterning was used to produce periodic cross-like surface patterns on commercial cylinder roller\nbearings. The wear behavior of as-patterned bearings was studied by a modified FE8 test rig under\nboundary lubrication. A mineral oil (ISO VG 100) as a base oil additivated with 0.02 wt % zinc\ndialkyldithiophosphate (ZDDP) was used for the tribological tests which were performed under\na Hertzian pressure of 1.92 GPa and maintained at 80 ââ??¦C and 20 rpm for 2 h. The laser-patterned\nbearings showed a significantly reduced mass loss by two orders of magnitude compared to the\nunpatterned reference bearings. A closer look at the samples proved the formation of the characteristic\nblue-colored ZDDP tribofilm on top of the laser-induced topography maximum positions. Due to the\nhigher contact pressure at the laser-induced peaks, the tribofilm formation was preferable at those\npositions thus protecting against wear. The laser patterns nearly remained unworn compared to the\nreference samples. A subsequent Raman analysis of the laser-patterned bearings clearly revealed the\nformation of zinc and iron sulfides as well as phosphates at the peak points.
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