Premium
Tribological properties and tribochemical mechanism of lanthanum and boron compounds in oil
Author(s) -
Jiang S.,
Wei Y. L.,
Cheng X. Y.,
Chen B. S.
Publication year - 2004
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.3010170106
Subject(s) - x ray photoelectron spectroscopy , lanthanum , auger electron spectroscopy , tribology , boron , materials science , decomposition , electron spectroscopy , chemical engineering , lanthanum oxide , adsorption , indentation hardness , metallurgy , inorganic chemistry , chemistry , microstructure , organic chemistry , oxide , physics , nuclear physics , engineering
Lanthanum dialkyldithiophosphate (LaDDP) was synthesised. The tribological properties of a combination additive of LaDDP and an organo‐borate (OB) in oil were evaluated with a four‐ball test machine. The results show that the combination of LaDDP and OB gives better load‐carrying capacity and anti‐wear and friction‐reducing properties than the individual components. Rubbed surfaces after the friction tests were investigated using X‐ray photoelectron spectroscopy, Auger electron spectroscopy, and microhardness testing. The results indicate that a boundary film is composed of deposit films (including La 2 O 3 and B 2 O 3 ), chemical reaction films (including FeSO 4 , FePO 4 , and FeS), and a tribodiffusion layer (including La and B). Lanthanum can promote the decomposition of OB and the tribodiffusion of boron. From a mass spectroscopy analysis a tribochemical mechanism is suggested.