Studies on the application of laser surface texturing to improve the tribological performance of AlCrSiN-Coated surfaces

Abstract

Recently, laser texturing has received lots of attention for improving the tribological performance of various surfaces, and this laser texturing of surfaces could be applied to improve the tribological performance of PVD coated surfaces. In this work two different patterns of laser surface texturing were performed on H13 substrate, and PVD AlCrSiN coatings with various N₂ contents were made by unbalanced magnetron sputtering on the textured H13 specimens. The coating characteristics such as crystalline structure, surface morphology, hardness, and friction coefficient of the coatings as a function of the N₂ partial pressure were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), microhardness tester, and wear test. Synthesis of the AlCrSiN thin films containing various N₂ contents was successful using the unbalanced magnetron sputtering process. A dense and compact microstructure, as well as a very smooth surface, were observed from the synthesized thin films, which could be attributed to the addition of Si into the AlCrN films, producing an amorphous phase in the films. Also the hardness of the AlCrSiN films increased with increasing N₂ partial pressures and the maximum hardness of approximately 33 GPa was measured from the AlCrSiN film synthesized with N₂ partial pressures of 0.16 Pa. From the wear tests against an Al₂O₃ counterpart ball at room temperature without lubrication, the average friction coefficient of the non-textured AlCrSiN films of 0.42 was decreased to 0.38 and 0.36 for dimple-textured and honeycomb-textured AlCrSiN films, respectively. Laser surface texturing on the AlCrSiN films reduced the friction coefficients by approximately more than 15%, and further improvement on the tribological performance of the textured surfaces could be possible by optimizing the honeycomb-textured surfaces.