Analysis of Infrared Spectra of Fluid Films in Simulated EHD Contacts

Abstract

Interferometry has provided the sensitivity needed for the gathering, through suitable windows, of infrared absorption and emission spectra of excellent resolution (<1 cm−1 ) from sample volumes even as small as EHD contact regions. Thus the power of molecular vibrational spectroscopy can be used to determine phase changes and structural changes in fluids subjected to conditions prevailing in EHD contacts. In this paper, some of the infrared methods are illustrated by the description of preliminary work in which the cavity of a high-pressure diamond anvil cell was used for contact simulation. Reference is made to a fluorescence-spectroscopic method of pressure determination in the diamond cell, which is also helpful in locating liquid/glass transition points.