# Tribological characteristics of composite brake pads under variable load and speed

## TL;DR

This study examines how load and speed affect the friction and wear of composite brake pads, showing that higher values lead to increased wear and reduced performance.

## Contribution

The study provides new insights into the tribological behavior of fiber-reinforced brake pads under varying operational conditions.

## Key findings

- Lower loads and speeds (10–20 N, 200–400 rpm) result in stable COF (0.63–0.72) and low wear rates (<0.85 mg/N).
- Higher loads (30 N) and speeds (800–1000 rpm) increase COF to 0.795 and wear rate to 1.065 mg/N due to protective layer breakdown.
- Microscopic analysis reveals fiber pull-out and matrix softening as key wear mechanisms under severe conditions.

## Abstract

This study investigates the tribological performance of fiber-reinforced composite brake pad materials fabricated using a compression molding technique. The work focuses on evaluating the influence of applied load (10–30 N) and rotational speed (200–1000 rpm) on the coefficient of friction (COF) and wear rate of the developed samples. Experimental tests were conducted using a pin-on-disc tribometer under controlled laboratory conditions to simulate braking contact. The results revealed that both parameters significantly affect the friction and wear behavior of the composites. At lower speeds (200–400 rpm) and loads (10–20 N), the COF remained relatively stable, ranging from 0.63 to 0.72, with a low wear rate below 0.85 mg/N, due to the formation of a compact tribo-film that protected the surface from severe abrasion. As the load and speed increased to 30 N and 800–1000 rpm, the COF increase to 0.795, and the wear rate increased to 1.065 mg/N, indicating the breakdown of the protective layer and the predominance of abrasive and adhesive wear mechanisms. Microscopic analysis using FESEM and EDS confirmed fiber pull-out, particle fragmentation, and localized matrix softening as the main surface features under severe conditions. These findings demonstrate a direct correlation between frictional stability and wear resistance, highlighting that the balance between operating load and sliding speed plays a crucial role in the durability and performance of composite brake pads.