Mechanical and tribological properties of ceramic-matrix friction materials with steel fiber and mullite fiber

• Interaction of mixing the steel and mullite fibers can improve the mechanical properties.
• Mixing the steel and mullite fibers can also improve friction stability.
• Friction coefficient increases with increasing additional mullite fiber content.
• Ceramic-matrix friction material shows sever fade due to mullite fibers agglomerated.

The purpose of the present work was to investigate and compare the mechanical and tribological behaviors of ceramic-matrix friction material (CMFM) with steel fiber (SF), mullite fiber (MF), and mixing SF and MF. The CMFM was prepared by hot-pressing sintering, and the tribological behaviors were determined using a constant speed friction tester. The worn surfaces and wear debris were observed by a scanning electron microscopy (SEM). Experiment results show that the combination of SF and MF can improve the mechanical properties that each single fiber does not have. The sever fade for the specimen reinforced by single MF during the whole friction testing can be attributed to the poor interface cohesive strength between MF and matrix. Mixing the SF and MF can improve the friction stability, and the friction coefficients for friction material with a mixture of the SF and MF increases with increasing MF content. For all specimens, increasing in the friction temperatures result in the increase of wear rates.