TY - GEN
T1 - High-thermal-conductivity densified graphitic foams as novel bearing materials
AU - Qu, Jun
AU - Blau, Peter J.
AU - Klett, James
AU - Jolly, Brian C.
PY - 2006
Y1 - 2006
N2 - The high-thermal-conductivity graphitic foams (foam-reinforced carbon-carbon composites) developed at ORNL have been mainly used for thermal management, as in heat sinks for electronic circuit boards and highly-efficient automotive radiators. However, recent studies in our laboratory have rather unexpectedly revealed their potential as novel bearing materials. In addition to their low density and potential for weight savings, there are three primary tribological advantages of the graphitic foam materials: (1) their graphitic structures provide self-lubricating qualities, (2) their extraordinarily high thermal conductivity aids in the efficient removal of frictionally-generated heat, and (3) the pores in the foam serve both as wear debris traps and lubricant reservoirs. Previous studies on the densified graphitic foam (DGF) sliding against steel and alumina at relatively low speed (1 m/s) and low load (10 N), revealed their encouraging selflubricating behavior, comparable to solid graphite while much better than bronze and polytetrafluoroethylene (Teflon™). In this study, pin-on-disk tests with higher speeds (2, 6, and 10 m/s) and higher loads (322 N) were conducted on DGF and graphite disks sliding against a DGF pin. The surface temperature on the graphite disk increased rapidly due to frictional heating and the friction coefficient increased proportionally with surface temperature when it was higher than 40°C. The DGF disk, however, ran much cooler due to the higher thermal conductivity, and more impressively, the friction coefficient remained low and constant even at elevated disk temperatures. This suggests high potential for the graphitic foam material in weight-sensitive, high-speed, and elevated temperature bearing applications.
AB - The high-thermal-conductivity graphitic foams (foam-reinforced carbon-carbon composites) developed at ORNL have been mainly used for thermal management, as in heat sinks for electronic circuit boards and highly-efficient automotive radiators. However, recent studies in our laboratory have rather unexpectedly revealed their potential as novel bearing materials. In addition to their low density and potential for weight savings, there are three primary tribological advantages of the graphitic foam materials: (1) their graphitic structures provide self-lubricating qualities, (2) their extraordinarily high thermal conductivity aids in the efficient removal of frictionally-generated heat, and (3) the pores in the foam serve both as wear debris traps and lubricant reservoirs. Previous studies on the densified graphitic foam (DGF) sliding against steel and alumina at relatively low speed (1 m/s) and low load (10 N), revealed their encouraging selflubricating behavior, comparable to solid graphite while much better than bronze and polytetrafluoroethylene (Teflon™). In this study, pin-on-disk tests with higher speeds (2, 6, and 10 m/s) and higher loads (322 N) were conducted on DGF and graphite disks sliding against a DGF pin. The surface temperature on the graphite disk increased rapidly due to frictional heating and the friction coefficient increased proportionally with surface temperature when it was higher than 40°C. The DGF disk, however, ran much cooler due to the higher thermal conductivity, and more impressively, the friction coefficient remained low and constant even at elevated disk temperatures. This suggests high potential for the graphitic foam material in weight-sensitive, high-speed, and elevated temperature bearing applications.
UR - http://www.scopus.com/inward/record.url?scp=33846028714&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:33846028714
SN - 0470080523
SN - 9780470080528
T3 - Ceramic Engineering and Science Proceedings
SP - 711
EP - 718
BT - Mechanical Properties and Performance of Engineering Ceramics and Composites II - A Collection of Papers Presented at the 30th International Conference on Advanced Ceramics and Composites
T2 - Mechanical Properties and Performance of Engineering Ceramics and Composites Symposium - 30th International Conference on Advanced Ceramics and Composites
Y2 - 22 January 2006 through 27 January 2006
ER -