Effect of micro-surface texturing on breakaway torque and blister formation on carbon-graphite faces in a mechanical seal

TLDR: In this paper, micro dimples were formed in controlled patterns on carbon-graphite surfaces with a laser and compared to silicon carbide surfaces that were not textured, and a higher rate of blister occurrence on laser textured carbon surfaces was attributed to the inherently low fracture toughness of carbon graphite materials and increased number of sites from which cracks could propagate.

Abstract: Micro-surface textures can create hydrodynamic and hydrostatic lift and thus they have the potential to reduce startup surface traction forces on mechanical seal faces. Lower surface traction forces will reduce the formation of the surface cracks that are commonly characterized as blisters. In this study, micro dimples were formed in controlled patterns on seal face surfaces with a laser. Tests were conducted with texture patterns on a carbon-graphite face or on a mating silicon carbide face. Fewer blisters were detected with textured silicon carbide faces in comparison to silicon carbide faces that were not textured. A higher rate of blister occurrence on laser textured carbon surfaces is attributed to the inherently low fracture toughness of carbon-graphite materials and the increased number of sites from which cracks could propagate.