The Tribological Properties of Several PTFE based self-lubricating composites in vacuum

Five commercial PTFE based self-lubricating composites were selected for candidates in space. The hardness was measured by depth-sensing indentation in CMC mode. The tribological properties of composites sliding against a 440C steel balls were investigated using a vacuum rotational ball-on-disc apparatus. The result show the hardness of Rulon 945, Rulon XL, GR 0348, D 5813 and LW 155 are about 62.01 MPa, 45.42 MPa, 84.62 MPa, 116.59 MPa and 569.40 MPa, which are higher than pure PTFE composite. The friction coefficient of Rulon 945, Rulon XL,GR 0348, D 5813, LW 155 obtained in vacuum are, 0.08 to 0.20, 0.06 to 0.10, 0.05 to 0.10, 0.06 to 0.10 and 0.05 to 0.15. Rulon XL, GR 0348 and D 5813 show very stable friction level around 0.08. For volumetric wear rate, D 5813 have the biggest volumetric wear rate of 2.36x10(-7)mm(3)/mm, which is twelve times of Rulon 945 and nearly five times of Rulon XL, GR 0348 and LW 155. Rulon XL and GR 0348 have the best friction and wear properties.