Effect of Diamond Content on Thermal, Mechanical, and Tribological Properties of Resin‐Based Friction Materials

ABSTRACT The friction and wear performance of friction materials for automotive brakes in high‐temperature environments is becoming increasingly important as service conditions become more complex. Resin‐based friction materials with different diamond contents were prepared using the hot press molding method, and their thermal, mechanical, and tribological properties were thoroughly examined. The results showed that the thermal properties of the materials decreased with the increase of diamond content, the mechanical properties showed different trends, and the wear mechanism evolved from abrasive wear to adhesive wear. The sample with 4 wt.% diamond added has the highest weight residue and 5% mass loss at 800°C, which are 92.9% and 742.9°C, respectively, while its compressive strength and modulus reach the maximum values of 159 and 2422 MPa, respectively. High content of diamond (12 wt.%) can be easily exposed and physically isolated at the wear interface, which leads to no friction film and increased adhesion on the surface of the sample. The low diamond content (4 wt.%) tends to generate abrasive debris and friction lubrication film at the wear interface, resulting in a high average friction coefficient (0.35–0.50) and the lowest volume wear rate (2–3 × 10 ⁻¹⁴ m ³ N ⁻¹ m ⁻¹ ) at high temperatures, with the best tribological property.