Tribopolymerization as a Novel Approach to Ceramic Lubrication

Abstract

It has been demonstrated that the principle of tribopolymerization developed by Furey and Kajdas can be used as a novel and effective approach to designing specific molecular structures for the lubrication of ceramic materials. We define tribopolymerization as the planned and continuous formation of protective polymeric films directly on tribological surfaces by the use of selected monomers capable of forming polymer films “in situ”. Over 40 experimental compounds selected, developed, or synthesized on the basis of this new concept were investigated in high stress sliding contact tests with various ceramic systems, i.e., alumina, zirconia, silicon nitride, and sapphire. Several of these were found to be strikingly effective as anti-wear additives. It was found that the addition of minor amounts (i.e., 1% or less) of particular compounds to a fluid hydrocarbon carrier, hexadecane, reduced ceramic wear by 40 to 80%. A reduction of wear by 80% corresponds to a five-fold increase in life.

We believe that the results are particularly significant since (a) ceramic materials are being used increasingly in a wide variety of mechanical devices and machines (e.g., high temperature engines) and (b) conventional approaches to the lubrication of ceramics are often limited or ineffective.

This paper summarizes the concept of tribopolymerization as a mechanism of boundary lubrication and discusses some of the more important discoveries made in applying this concept to the difficult problem of ceramic lubrication. The research was conducted in the Tribology Laboratory at Virginia Polytechnic Institute and State University.