Evolution of contact surface characteristics and tribological properties of a copper-based sintered material during high-energy braking

Abstract

A plethora of difficulties may appear with brake materials during braking with high-energy dissipation. The tribological properties of a copper-based sintered material for high-energy brakes at different levels of braking energy ranging from 3010 to 31,789 J/cm2 were experimentally evaluated using a reduced-scale dynamometer. Morphological analysis of worn surfaces and wear debris analysis were conducted using scanning electron microscope and three-dimensional video microscope, respectively. Friction and wear behaviour of the copper-based sintered material depended strongly on the contact surface characteristics, being controlled by the dissipation of braking energy. The worn surfaces with low roughness, well-covered by the tribo-films, contributed to the low and stable friction coefficient. Additionally, examination and analysis of worn surfaces and wear debris corroborated the wear mechanisms of the copper-based sintered material. Severe adhesive wear and delamination wear occurred during high-energy braking.