Abstract
Sliding tests with a pin-on-disc tribometer and both sliding and rolling tests with a modified four-ball tester at bulk temperatures of about 500 °C and initial contact pressures of about 2.2 GPa have demonstrated up to 80% reductions of friction and wear with silicon nitride surfaces when a stream of ethylene is directed into the conjunction region. The effects are even more pronounced when the ethylene is prenucleated by a flow over a coil of nichrome wire electrically heated to about 800 °C and located about 30 cm upstream of the exit nozzle. Steel and Ni-plated steel are lubricated by this method even more efficiently and at lower temperatures. The underlying mechanism is probably analogous to that of hydrocarbon pyrolysis by flash photolysis, which was studied by Porter in the 1950s, with the rapid heating to the "flash temperatures" and subsequent cooling occurring naturally in friction contacts. The observation that pyrolysis of hydrocarbons to solid carbon occurs in two stages, nucleation and particle growth, has allowed their physical separation, the former taking place in the ethylene stream and the latter in the frictional contact some distance away.
Original language | English |
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Pages (from-to) | 498-507 |
Number of pages | 10 |
Journal | Wear |
Volume | 162-164 |
Issue number | PART A |
DOIs | |
State | Published - Apr 13 1993 |
Scopus Subject Areas
- Condensed Matter Physics
- Mechanics of Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry