LUBRICATION OF SI3N4 AND STEEL ROLLING AND SLIDING CONTACTS BY DEPOSITS OF PYROLYZED CARBONACEOUS GASES

Pin-on-disk and four-ball tests with steel and silicon nitride surface s can be lubricated by carbon deposited as a result of pyrolysis in th e tribo-contacts of ethylene or other carbonaceous gases at bulk tempe ratures in excess of 500-degrees-C. The carbon deposits were analyzed and shown to be different for different gases. Substantial improvement s could be achieved by insertion of a hot wire into the ethylene strea m. This was shown to be equivalent to an admixture of a small amount o f acetylene. Since carbon deposit formation from pure ethylene was enh anced by the presence of acetylene carbon, the carbon and not the gase ous acetylene was the catalyst for enhanced formation of lubricating c arbon. Lubrication was also achieved with the carbon formed from a fee d gas of carbon monoxide and hydrogen.