Wear and Friction-Induced Vibration of Brake Friction Materials with Different Weight Average Molar Mass Phenolic Resins

• Published in: Tribology letters Vol. 58; no. 1; pp. 1 - 8
• Main Authors: Shin, M. W., Kim, J. W., Joo, B. S., Jang, H.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.04.2015; Springer Nature B.V
• Subjects: Brakes; Braking systems; Chemistry and Materials Science; Corrosion and Coatings; Critical velocity; Friction; Friction reduction; Materials Science; Nanotechnology; Original Paper; Phenolic resins; Physical Chemistry; Polymers; Resins; Stability; Stiffness; Surfaces and Interfaces; Theoretical and Applied Mechanics; Thin Films; Tribology; Vibration; Wear rate; Weight; Stick-slip; Sliding wear; Wear; Brake/clutch materials; Phenolic resin; Fade; Average molecular mass
• ISSN: 1023-8883; 1573-2711
• DOI: 10.1007/s11249-015-0486-5

The friction and wear of brake friction materials containing phenolic resins with different weight average molecular masses ( M w  = 2.2–6.1 kg/mol) were investigated using a Krauss-type tribometer and a reduced-scale dynamometer. The results demonstrated that the friction level, wear rate, and friction instability were strongly affected by the M w of the phenolic resin, attributed to the different shear strengths of the friction materials. The high- M w phenolic resin exhibited an increased friction level while reducing the wear rate, with both effects more pronounced at temperatures above the phenolic resin decomposition temperature. The friction materials containing the higher- M w phenolic resins also showed an improved friction instability, revealing a lower critical velocity for the incidence of friction oscillation. The stiffness measured from the friction material revealed that the M w did not change the surface stiffness after the friction tests, indicating that the improved friction-induced vibration of the friction material with the high- M w phenolic resin was attributed to an increased matrix stiffness rather than to the sliding surface.