Interfacial antiwear and physicochemical properties of alkylborate-dithiophosphates
Shah, Faiz Ullah, Glavatskih, Sergei, Höglund, Erik, Lindberg, Mats and Antzutkin, Oleg N.. (2011) Interfacial antiwear and physicochemical properties of alkylborate-dithiophosphates. ACS Applied Materials & Interfaces, Vol.3 (No.4). pp. 956-968. ISSN 1944-8244Full text not available from this repository.
Official URL: http://dx.doi.org/10.1021/am101203t
Boron compounds have become of interest in tribology because of their unique tribochemical and tribological properties. At the same time, dialkyldithiophosphates (DTPs) of transition metals have been extensively used as multifunctional additives in lubricants to control friction and reduce wear in mechanical systems. Because of the environmental pollution and health hazards of these compounds, ashless compounds with reduced amounts of sulfur and phosphorus are desirable. This work reports on the synthesis, characterization, and tribological properties of a new class of compounds, alkylborate-dithiophosphates. This class combines two high-iron-affinity surface active groups, borate and dialkydithiophosphate, into a single molecule. The final products, viscous liquids, were characterized by FT-IR, multinuclear (13)C, (13)P, and (13)B NMR spectroscopy and thermal analyses. Residues of one representative compound from this class, DPB-EDTP, after thermal analyses were additionally characterized by multinuclear (13)C, (31)P and (11)B MAS and (31)P CP/MAS NMR spectroscopy. Solid-state NMR data suggest that a dominant part of the solid residue of DPB-EDTP consists of borophosphates. Antiwear and friction properties of a mineral oil with these novel additives were evaluated in a four-ball tribometer in comparison with O,O'-di-n-butyl-dithiophosphatozinc(II), Zn-BuDTP, as a reference lubricant additive. The surface morphology and the elemental composition of the tribofilms were characterized using scanning electron microscopy with energy-dispersive X-rays spectroscopy (SEM/EDS). The results show that alkylborate-dithiophosphates, with substantially reduced amounts of sulfur and phosphorus compared with Zn-BuDTP, have considerably better antiwear and friction performance.
|Item Type:||Journal Article|
|Subjects:||Q Science > QC Physics|
|Divisions:||Faculty of Science > Physics|
|Journal or Publication Title:||ACS Applied Materials & Interfaces|
|Publisher:||American Chemical Society|
|Official Date:||April 2011|
|Page Range:||pp. 956-968|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Swedish Council for Planning and Coordination of Research (FRN), Foundation in memory of J. C. and Seth M. Kempe|
|Grant number:||JCK-2003 JCK-2307 JCK-2905 (Foundation in memory of J. C. and Seth M. Kempe)|
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