Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
619339 | Wear | 2009 | 7 Pages |
Abstract
Due to their thermo-mechanical performances maintained at high temperature, C/C composites demonstrate their advantages in high energy aeronautical braking. During friction a typical tribological behavior was observed. At first, an abrupt transition of friction coefficient takes place systematically from a weak value (â¼0.15) to a high value (â¼0.35). Before this transition, an extremely weak wear rate is associated to a weak friction coefficient value and no gas exchanges occur in the contact, this regime being called non-reactive. From the abrupt transition, a very high wear rate and strong gas exchanges associated to the high friction value occur (reactive regime). In this paper, for a better understanding of the mechanisms governing the abrupt transition during C/C composites tribological, mechanical, thermal and physico-chemical data are analyzed. Friction tests are performed on a 3D C/C composite consisting of PAN-based fibers and CVI pyrocarbon matrix in using a pin-on-disc tribometer equipped with a mass spectrometer allowing the in situ gas exchange analysis (CO2 production, O2 consumption) in the contact. To follow the disc surface temperature evolution before, during and after the transition, a thermal infrared camera is used. After friction, worn surfaces and interfaces are characterized by optical microscopy and scanning electron microscopy. In a final analysis, a mechanism is proposed to explain the abrupt transition.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Colloid and Surface Chemistry
Authors
H. Kasem, S. Bonnamy, Y. Berthier, P. Dufrénoy, P. Jacquemard,