Influence of surface treatment of elastomers on their frictional behaviour in sliding contact

To reduce friction of elastomer parts moving against a metal counter body in dry conditions, two different surface treatment techniques were applied on elastomer parts: laser cladding and plasma treatment at atmospheric pressure. Polyamide 11 (PA 11) based coatings were produced on thermoplastic polyurethane (TPU) substrates by laser cladding. During ball-on-disc tribotesting the effect of a PA 11 coating was identical to that of a PA 11 + 9% MoS2 coating: friction of the TPU substrate was reduced with 40%. The incorporation of 15 wt% PTFE in the PA 11 coating resulted in a further decrease of the frictional force. A reduction of 80% of the frictional force of the TPU substrate was measured. The surface of the coatings before and after tribotesting was analysed. The plasma treatment of HNBR was done using a Plasmaspot® to form a plasma polymerised coating based on two different types of siloxanes. A reduction of 74–80% of the initial friction coefficient was measured in two different tribotest rig configurations: ball-on-disc and disc-on-disc. The resulting wear tracks were analyzed by SEM and EDX.