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A study of the tribological behaviour and mechanism of actoin of bismuth dialkyldithiophosphate
Author(s) -
Chen L.,
Dong J.,
Chen G.
Publication year - 1998
Publication title -
lubrication science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.632
H-Index - 36
eISSN - 1557-6833
pISSN - 0954-0075
DOI - 10.1002/ls.3010110102
Subject(s) - bismuth , mechanism (biology) , tribology , materials science , chemical engineering , chemistry , metallurgy , engineering , philosophy , epistemology
This paper discusses the preparation of bismuth dialkyldithio‐phosphate as an oil‐soluble antiwear and extreme pressure additive for lubricants. Its tribological performance when added to an ISO VG32 mineral oil was evaluated on a four‐ball tester and a ring‐on‐block machine. The relationships between its performance and the concentrations are also given, and are compared with those of zinc dialkyldithiophosphate (ZDDP). The results show that the compound not only possesses good antiwear and friction‐reducing abilities, but also has a higher load‐carrying capacity than ZDDP. The mechanism of action of the additive was studied by surface analysis. A scanning Auger microprobe revealed a high bismuth content in the rubbing surface layers, and X‐ray photoelectron spectroscopy detected the formation of various chemical species including organic films, metallic bismuth, bismuth oxide, and bismuth sulphide. The mechanism of action is postulated on the basis of these results.