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Effect of rare earth compounds as fillers on friction and wear behaviors of PTFE‐based composites
Author(s) -
Zhang ZhaoZhu,
Xue QunJi,
Liu WeiMin,
Shen WeiChang
Publication year - 1999
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19990418)72:3<361::aid-app6>3.0.co;2-5
Subject(s) - polytetrafluoroethylene , materials science , scanning electron microscope , composite material , composite number , bearing (navigation) , friction coefficient , cartography , geography
The friction and wear behaviors of polytetrafluoroethylene (PTFE)‐based composites filled with rare earth compounds CeO 2 , CeF 3 , and La 2 O 3 in volume content from 5 to 30% sliding against GCr15 bearing steel under dry friction conditions were evaluated by using an MHK‐500 ring‐block wear tester. The wear debris and the worn surfaces of the PTFE composites were investigated by using a scanning electron microscope (SEM), whereas the transfer films of the PTFE composites formed on the surface of GCr15 bearing steel were examined by using an optical microscope. Experimental results show that the antiwear properties of the PTFE composites can be improved greatly by filling PTFE with different contents of CeO 2 , CeF 3 , and La 2 O 3 , and that the wear of the PTFE composites can be decreased by one to two orders of magnitude compared with that of pure PTFE. The wear of the CeF 3 ‐filled PTFE composite decreases with the increase of the content of CeF 3 from 5 to 30 vol %, but its friction coefficient increases with the increase of the content of CeF 3 in PTFE. When the content of CeO 2 in PTFE is 15 vol %, the friction and wear properties of CeO 2 ‐filled PTFE composite are the best. But when the content of La 2 O 3 in PTFE is between 15 and 20 vol %, the PTFE composite filled with La 2 O 3 exhibits excellent friction and wear‐reducing properties. Microscope investigations show that rare earth compounds CeO 2 , CeF 3 , and La 2 O 3 in PTFE not only inhibit the large‐scale destruction of the banded structure of PTFE but also enhance the adhesion of the transfer films of the PTFE composites to the surface of GCr15 bearing steel, so they greatly reduce the wear of the PTFE composites. With the increase of the content of CeO 2 , CeF 3 , and La 2 O 3 in PTFE, the actions with which the rare earth compounds inhibit the large‐scale destruction of the banded structure of PTFE are enhanced; so the wear of the PTFE composites decreases. Meanwhile, because CeO 2 ‐ and La 2 O 3 ‐filled PTFE composites can easily form uniform transfer films on the surface of GCr15 bearing steel, the friction and wear‐reducing properties of CeO 2 ‐ and La 2 O 3 ‐filled PTFE composites are better than those of CeF 3 ‐filled PTFE composites under dry friction conditions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 361–369, 1999