Enhanced Tribological Property of Mechanical Seal in Water Environment by Nanosecond Laser Surface Texturing

Mechanical seal used in turbopump of liquid rocket engine always underwent sever wear and fric-tion-induced vibration in the running stage. Here, an effective circle-shaped texture dimple was proposed to be manufactured on S07 steel surface, and its surface morphology, mechanical property and tribological performance were investigated systematically. To simulate the low viscosity of sealed liquid in the turbopump, the tribology test was conducted in water environment. Textures with different area ratios were manufactured and the experimental results showed that the texture whose area ratio is 10% (T10) is the most efficient. More tribological experiments under different temperatures, frequencies and loads were conducted, and the results showed that the T10 textured surface can decrease the friction coefficient, enhance the stability of friction behaviors and reduce wear rate. Moreover, the tribological mechanism of the texture was explored and analyzed according to the SEM and EDS of the wear tracks. The soft Cu/graphene composite can fill the texture dimples and form a tribo-film on the surface, which helps to reduction of friction and wear.