Detection of tribochemical reactions using photoelectron emission microscopy

Abstract

The thermal decomposition of trifluoroacetic acid on a Mo(100) is studied using high resolution electron energy loss spectroscopy. It is found that trifluoroacetic acid (CF3COOH) exposed to the Mo(100) surface at room temperature deprotonates to form a trifluoroacetate species (CF3COO–). Further decomposition of the acetate species is observed resulting in the formation of an intermediate species and possibly ionic fluorine adsorption at elevated temperatures. Dynamic photoelectron emission microscopy images are obtained from a rotating, cylindrical molybdenum sample. This real-time imaging of a rotating sample lays the foundation for imaging various tribo-induced reactions in real time. First experiments employing the rotating cylindrical sample, the adsorption of trifluoroacetic acid and how such experiments may clarify the mechanisms for lubricant degradation are discussed.