Effects of the etching process on the surface, friction and wear characteristics of silicone rubber coated with micro-sized ceramic particles

Abstract

This study investigates the friction and wear characteristics of silicone rubber used in hydraulic systems, focusing on surface properties achieved through coating strategies. Silicone rubber specimens with varying surface characteristics, prepared by coating with micro-sized ceramic particles and employing etching processes, were examined. Surface morphology, roughness, water droplet contact angles, and friction and wear characteristics were evaluated. The silicone rubber was coated with ceramic particles (average size: 16 μm) and subsequently etched for different durations (1, 5, 10, 30, and 60 minutes). The results revealed that longer etching times led to increased surface roughness, while shorter etching times resulted in improved wear characteristics. The friction coefficient demonstrated a discernible reduction with escalating etching durations, with Etching-60M showing approximately 50% lower friction coefficient compared to Etching-1M. Wear rates ranged from 2.47 × 10⁻⁷ to 1.43 × 10⁻⁶ mm³ N⁻¹ mm⁻¹, indicating an increasing trend with longer etching times. Distinct wear mechanisms were observed between non-etched and etched specimens, with the latter exhibiting more pronounced wear tracks. Finite element analysis highlighted variations in stress behavior during contact sliding, indicating that surface modifications significantly impact wear resistance. While longer etching times improved friction characteristics, shorter etching times yielded superior wear characteristics. Further research is recommended to explore optimal etching conditions considering various variables.