Enhanced Performance of Eco-friendly Brake-pads by Using Plasma Treated Metallic Particles

Metallic particles in various amounts are commonly used in the brake-pad-formulations to improve the friction, mechanical strength, thermal conductivity, heat dissipation, fade etc. The same metallic particles, however, lead to increase in wear. To overcome the wear related problem and to improve the tribo-performance further, wettability/surface free-energy (SFE) of metallic particles needs to be improved so that they will not be easily dug out contributing to higher wear that without metal particles. Current era is of copper-free friction materials. Hence, in this work, stainless steel particles (SSPs) and copper particles were treated with low pressure argon plasma gas using optimised processing parameters (viz., gas- Argon, power- 500 W, treatment time-20 min.,). A series of four multi-ingredient brake-pads using identical composition but differing in the theme-ingredients (3 vol.%) was developed. First two types of brake-pads were based on untreated identical sized particles (SSPs and Cu) and another two types of brake-pads were based on plasma treated particles. One more type of brake-pad was developed without metallic particles. The developed brake-pads were evaluated for different physical, mechanical and chemical properties. Tribological performance was evaluated on a full-scale dynamometer following test schedule (JASO C406). Additionally, noise-vibration (NV) performance was evaluated on NV test rig following SAE J 2521 (partly) test schedule. Results revealed that most of the tribological properties along with NV properties were improved for treated particles in brake-pads. The topography of worn brake-pads was done to understand the wear mechanisms.