Tribological, physicochemical and thermal study of the abrupt friction transition during carbon/carbon composite friction

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• 作者：H. Kasem ; S. Bonnamy ; Y. Berthier ; P. Dufré ; noy ; P. Jacquemard
• 关键词：C/C composite ; Friction transition ; Thermal measurement ; Mass spectroscopy
• 刊名：Wear
• 出版年：2009
• 出版时间：15 June 2009
• 年：2009
• 卷：267
• 期：5-8
• 页码：846-852
• 全文大小：1653 K

文摘

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 (0.15) to a high value (0.35). 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.