Laser surface texturing of gray cast iron for improving tribological behavior

Laser surface texturing process involves creation of microfeatures, e.g., tiny dimples, usually distributed in a certain pattern, covering only a fraction of the surface of the material that is being treated. The process offers several advantages for tribological applications, including improved load capacity, wear resistance, lubrication lifetime, and reduced friction coefficient. In the present study, the surface modification of gray cast iron, using millisecond (\u3bb\ua0=\ua01,064\ua0nm), nanosecond (\u3bb\ua0=\ua01,064\ua0nm) and femtosecond (\u3bb\ua0=\ua0800\ua0nm) pulse duration laser irradiation, is adopted to establish a particular geometrical pattern with dimple features and dimensions, to improve wear and friction behavior. The effect of various laser processing parameters, including laser pulse energy, pulse duration and processing speed, on the performance characteristics of the laser-treated samples is investigated. The microtextured surfaces were produced on gray cast iron using different millisecond (0.5\ua0ms), nanosecond (40\ua0ns) and femtosecond (120\ua0fs) laser source with the dimple depth between 3 and 15\ua0\u3bcm. The coefficient of friction for the untextured surface was ~0.55, millisecond laser textured ~0.31, nanosecond laser textured ~0.02 and femtosecond laser ~0.01, under normal force of 50\ua0N and sliding speed of 63\ua0mm/s. Surface texturing of the gray cast iron surface using femtosecond pulse duration resulted in significant improvement in wear resistance in comparison to the untextured as well as millisecond and nanosecond laser-textured surface. \ua9 2014 Springer-Verlag Berlin Heidelberg.Peer reviewed: YesNRC publication: Ye