Effect of zinc powder content on tribological behaviors of brake friction materials
(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Hunan Boyun Automobile Brake Materials Co., Ltd., Changsha 410205, China;
3. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China)
2. Hunan Boyun Automobile Brake Materials Co., Ltd., Changsha 410205, China;
3. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China)
Abstract: Brake friction materials with different zinc powder contents (0, 2, 4, 6, 8 wt.%) were fabricated via powder metallurgy method. The results indicate that with the increasing zinc powder content, the density and thermal conductivity of the materials gradually increase, while the hardness decreases monotonously. With increasing zinc powder content, the curve of the nominal friction coefficient shows fluctuating trend but the lowest friction coefficient also shows an increase. However, the wear rate and braking noise of the friction material monotonously decrease with increasing zinc content. This effect may be attributed to the transformation of the tribological mechanism from adhesive wear and abrasive wear to adhesive wear. The brake friction material with 4 wt.% zinc powder exhibits both the best tribological and noise performance.
Key words: zinc powder content; brake friction material; tribological behavior; braking noise