Synergistic effects between phosphonium-alkylphosphate ionic liquids and zinc dialkyldithiophosphate (ZDDP) as lubricant additives

Jun Qu; William C Barnhill; Huimin Luo; Harry M Meyer 3rd; Donovan N Leonard; Alexander K Landauer; Bassem Kheireddin; Hong Gao; Brian L Papke; Sheng Dai

doi:10.1002/adma.201502037

Synergistic effects between phosphonium-alkylphosphate ionic liquids and zinc dialkyldithiophosphate (ZDDP) as lubricant additives

Adv Mater. 2015 Aug 26;27(32):4767-74. doi: 10.1002/adma.201502037. Epub 2015 Jul 14.

Authors

Affiliations

¹ Materials Science and Technology Division, Oak Ridge National Laboratory, P. O. Box 2008, MS-6063, Oak Ridge, TN, 37831-6063, USA.
² Energy and Transportation Science Division, Oak Ridge National Laboratory, P. O. Box 2008, MS-6181, Oak Ridge, TN, 37831-6181, USA.
³ Technology Center Houston, Shell Global Solutions, Houston, TX, 77082-3101, USA.
⁴ Chemical Sciences Division, Oak Ridge National Laboratory, P. O. Box 2008, MS-6201, Oak Ridge, TN, 37831-6201, USA.

PMID: 26173561
DOI: 10.1002/adma.201502037

Abstract

Unique synergistic effects between phosphonium-alkylphosphate ionic liquids (ILs) and zinc dialkyldithiophosphate (ZDDP) are discovered when used together as lubricant additives, resulting in significant friction and wear reduction along with distinct tribofilm composition and mechanical properties. The synergism is attributed to the remarkably 30-70× higher-than-nominal concentrations of hypothetical new compounds (via anion exchange between IL and ZDDP) on the fluid surface/interface.

Keywords: ZDDP; friction and wear reductions; ionic liquids; lubricant additives; synergistic effects.