Michael J. Furey - US grants

The primary objective of this research is to obtain a better understanding of tribopolymerization--the planned or intentional formation of polymeric films directly on rubbing surfaces--as a mechanism of boundary lubrication, with special emphasis on the role of surface temperatures on the process. The behavior of selected monomers capable of forming surface polymers under tribological contact by polycondensation as well as addition reactions will be investigated in a research program which couples the following experimental systems or techniques: (a) an advanced rotating sapphire disk/infrared microscope device to determine surface temperatures produced by friction; (b) surface analytical techniques- -including Fourier Transform Infrared Spectroscopy--to study the characteristics of thin polymer surface films formed; and (c) other methods which couple thermal effects with surface reactions and polymerization. The significance of this research is that it represents a rational and innovative approach to the design of chemical structures to act as boundary lubricants to reduce wear and surface damage in tribological processes. Unlike conventional antiwear additives which chemically react with the solid surface (e.g., iron) to from a protective layer, this approach involves the deposition of a surface film which acts to reduce adhesion, wear, and damage. The principal investigators believe that a better understanding of the tribopolymerization process-- including the role of surface temperature, catalysis, and electron emission in tribological contact--will open the door to new, extremely effective, and unconventional approaches to minimizing wear in a wide variety of systems. This should make it possible to design specific antiwear additives for given tribological systems.

Fretting fatigue and fretting corrosion are common types of tribological damage caused by oscillating contacts. The level of surface temperature generated by friction in the contact zone under these conditions and its effect on the fretting process will be studied. Experimental temperature measurements obtained by infrared microscopy will be combined with tribological fretting data and with relevant heat transfer analyses to formulate a model for the role of temperature in fretting damage. Effects of sliding distance and velocity as well as of oxide films will be included. The study will result in a better understanding of the fretting process and could lead to better guidelines for materials selection and development for fretting conditions.

9531661 Furey Triboemission particles emitted from sliding ceramic pairs will be measured and characterized by type and amount as functions of time, applied load, velocity, ambient atmosphere, and the presence of various compounds. Their possible role in the formation of tribopolymers will be evaluated theoretically and confirmed experimentally through tests with various addition-type monomers in the sliding contact zone, followed by examination of the wear scars and the surrounding surface by surface analytical techniques. ***