Anti-wear chemistry of ZDDP and calcium borate nano-additive. Coupling experiments, chemical hardness predictions, and MD calculations

Jean Michel Martin, Tasuku Onodera, Maria Isabel De Barros Bouchet, Nozomu Hatakeyama, Akira Miyamoto

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

Zinc dialkyl dithiophosphate (ZDDP) is an anti-wear additive for steel surfaces currently used in engine oils. Its anti-wear performance (against abrasion) is due to tribochemical reaction of zinc polyphosphate with abrasive metal oxides nanoparticles, under the combined effect of pressure and shear. However, phosphorous and sulfur are nocuous for environmental issues. Borates are possible candidates to replace phosphates in engine oils. Friction reduction with borates is found to be better than ZDDP but the anti-wear efficiency of borates is lower. In this work, we show how chemical hardness model and computer simulation can explain these different behaviors. Also we show that molecular dynamics is able to predict accurately behavior of mixtures of phosphates and borate. Results show that mixtures of additives with a P:B ratio slightly above unity can be a good compromise to have both good tribological performance and low content of phosphorous and sulfur in the lubricant.

Original languageEnglish
Pages (from-to)95-104
Number of pages10
JournalTribology Letters
Volume50
Issue number1
DOIs
Publication statusPublished - 2013 Apr

Keywords

  • Borate additives
  • MD calculation
  • XPS analysis

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

Fingerprint Dive into the research topics of 'Anti-wear chemistry of ZDDP and calcium borate nano-additive. Coupling experiments, chemical hardness predictions, and MD calculations'. Together they form a unique fingerprint.

Cite this