Tribological Effects of Martian Regoliths on Stainless Steel with Natural and Composite Lip Seal and Packing Materials

We have investigated the sealing performance of different sealants and the abrasive effect of some Martian regolith simulants (MGS-1 and JEZ-1) by pin-on-disc tests using steel and various pin material pairs. Pin materials, representing sealants, were present in the following two forms: block types, such as pure polytetrafluoroethylene (PTFE) and composite PTFE, as well as braided pins, including pure and hybrid composite PTFE. Friction resistance, wear, surface roughness, and electron microscopy analyses were used to evaluate the tribological properties. We found significant differences between the block-type and braided pin materials regarding the sealing and wear performance. The braided pins either reached stabilized coefficients of friction at a much higher level (0.55) than the block-type pins or did not stabilize at all during the longest test duration. Martian regoliths resulted in negligible wear regarding the disc, but the hybrid composite braided pins were severely worn, causing the abrasion test to be stopped before schedule.