Laser surface micro-texturing on the mechanical seal rings for enhancing the tribological properties

摘要

Laser texturing was performed on the sliding surface of silicon carbide sealing rings, in order to investigate the surface modification in relationships with the laser processing parameters and the tribological performances of the mechanical face seals. As no graphs or data sheets were found in literature on the surface absorption (or reflection) properties of the SiC versus the laser wavelengths, it was necessary to execute a series of screening tests using different laser sources, wavelengths (0.532 mum, 0.810 mum, 1.06 mum and 10.6 mum) and modes (Normal and Q -Switch) to verify the surface absorption properties of the SiC seal faces. So far, only the pulsed CO_2 laser irradiation was proved to be efficient in producing regular shaped holes. Hole size and microstructural modification were related to laser power, pulse duration and spot size. Under selected processing conditions, seal faces were regularly textured producing microholes (80 to 100 mum diameter) at a distance of about 200 mum (center to center of the holes). Tribological performances of these mechanical seals under specific proof tests evidenced the increase of the fluid film stiffness and seal life and the reduction of friction coefficient and torque values.