X-Ray Photoelectron Spectroscopy Investigation of Tribochemical Properties of Biolubricants
Bio-oils Research Unit
2012 Annual Report
1a.Objectives (from AD-416):
The objective of this agreement is to conduct in depth understanding of the tribochemical reactions that occur during lubrication with biobased lubricants. Such investigation will allow for elucidating the reactants, the products, and the reaction mechanism occuring during a biolubrication process. Understanding of tribochemical reactions will allow for designing and synthesizing new biobased lubricant ingredients with superior oxidation stability, cold flow, and a number of tribological properties.
1b.Approach (from AD-416):
Model bio-based ingredients will be used in extreme pressure tribological investigations on a 4-ball tribometer. The wear surfaces from such an investigation will be analyzed by x-ray photoelectron spectroscopy (XPS). The analytical results will be used to construct a hypothesis of the potential reaction mechanisms at the tribological interface. The hypothesis will be refined further with additional carefully designed experiments.
Extreme pressure (EP) additives that are commercially available and widely used in lubricant formulations were used at ARS in EP tests to generate specimens to be used in x-ray photoelectron spectroscopy (XPS) investigations. These specimens will be used to establish baseline data at the University of Illinois at Urbana-Champaign (UIUC). This is a very important step in verifying if the method can be used in our studies on novel and bio-based EP additives. Colleagues at UIUC have already taken the necessary training to use XPS and conduct the investigations.