Ceramic lubrication: vapor phase tribopolymerization and a new high speed, high load pin-on-disk machine
An experimental study of ceramic lubrication through the concept of tribopolymerization from the vapor phase is presented. Four vinyl monomer additives were studied, i.e., vinyl acetate, diallyl phthalate, lauryl methacrylate, and vinyl octadecyl ether. The liquid additives were heated, vaporized, and delivered to an enclosed alumina-on-alumina "pin-on-disk” contact region by a stream of dry nitrogen gas.
Alumina ball wear reductions of up to 99% were observed and total wear reductions (ball and disk) of over 70% were also common. Colorful surface films visible to the naked eye were examined. Monomer concentration does not appear to have an effect over the range examined. But, higher monomer delivery temperatures have a significant beneficial effect in reducing wear. Selective FTIRM analysis shows evidence of both polymerization and monomer reactions with the alumina surface. It is believed that the surface films formed reduce adhesion and therefore decrease both wear and friction.
The development, design, and construction of a high load, high speed, high frictional heat generation pin-on-disk machine is presented. A very successful geometry has been created and recommendations for added instrumentation and its future use for both liquid and vapor phase tests are presented.