Assessing Friction Stress on a Liquid Lubricant by Stable Isotope Analysis

Abstract

Compound-specific stable isotope analysis (CSIA) was applied to a pentaerythritol ester lubricant to determine if predictable fractionation effects could be related to friction stress. A pin-on-disk tribometer was used to expose the lubricant to five doubly-increasing sliding distances (up to 36 km). PCA was used to ordinate multivariate data and test if significant isotopic shifts or FTIR spectral changes could be related to sliding cycles. 13C Isotope ratios only were found to be statistically different (P <0.05) between treatments. PCA gave a primary score (PC1) containing 44% of the 13C-isotopic variability, which correlated exponentially with sliding cycles (r2 = 0.96). A peak, not present in unexposed lubricant, became evident and showed increasing 13C depletion with increasing length of sliding exposure.

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Document Details

Document Type
Technical Report
Publication Date
Jul 17, 2014
Accession Number
ADA610703

Entities

People

  • Kathryn Wahl
  • Randolph K. Larsen Iii
  • Thomas J. Boyd

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Analysis Of Variance
  • Chemical Compounds
  • Chemical Kinetics
  • Chemical Reactions
  • Chemical Synthesis
  • Chemistry
  • Chlorides
  • Combustion
  • Data Analysis
  • Friction
  • Information Science
  • Isotopes
  • Lubricants
  • Military Research
  • Standards
  • Statistical Analysis
  • Statistical Tests

Readers

  • Analytical Chemistry
  • Regression Analysis.
  • Tribology (the study of the boundary interaction between sliding surfaces, lubrication, wear and friction).