Structural evolution and wear of ice surface during rubber–ice contact

• Wear features of ice surface generated during friction testing with rubber compounds.
• Rubber–ice contact mechanisms at different length scales.
• 3-D characterization of microscopic ice surface.

This study investigates different possible contact mechanisms of rubber–ice sliding friction using in-situ and ex-situ ice microscopy at test temperatures below melting point. Several frictional processes were identified based on the evolution of ice surface morphology. The nature of rubber–ice contact is significantly different for softer and stiffer rubber compounds. For softer compounds the ice microstructure evolves through frost rounding/removal, surface scratching by hard filler plowing, and shearing of quasi-liquid layer by capillary drag. Cold recrystallization and local melting/refreezing of ice was not found to occur owing to homogenous pressure distribution. For stiffer compounds, the pressure distribution is uneven and contact is more localized, resulting in enhanced local deformation features such as subgrain boundaries, visible etch pits and large-scale melting/refreezing.