Influence of surface texture on boundary lubricated sliding contacts

Testing scuffing resistance of materials for marine 2-stroke engines – Difficulties with lab scale testing of a complex phenomenon

“…Thereafter, severe wear occurred. Similar behaviour, where the large surface area of a relatively small volume of fine wear debris adsorbs oil, thus aggravating the starved lubrication situation, was also shown by Pettersson and Jacobson [22]. Another variant for involvement of wear debris in scuffing initiation was suggested by Enthoven and Spike [12].…”

“…It is commonly assumed to be an advantage to use materials with an ability to contain oil in reservoirs such as pores and cavities. This has also been shown experimentally for instance by Pettersson and Jacobson [22]. Furthermore, if the entrapment of wear debris is an important factor for scuffing initiation (as discussed), wear debris could become trapped in the cavities rather than between the sliding surfaces.…”

“…Such a layer has a negative effect by polishing the liner surface, but even when a piston scraper ring is used to scrape it off, the scuffing risk remains higher. We could speculate that this is due to wear particles from the scraped layer, which could lead to ruined lubrication in the same way as in the lab experiments [22].…”

FZG Gear Efficiency and Pin-on-Disc Frictional Study of Sintered and Wrought Steel Gear Materials

“…The low gear mesh torque loss and friction coefficient of RS-AQ combination are mainly due to the porosities on the surfaces of the AQ parts, which act as oil reservoirs to supply enough lubricant to lubricate the contact surfaces. References [10][11][12] show that controlled dimples on contact surfaces act as lubricant reservoirs and play a role in promoting better lubrication and a decrease in friction. By calculation, the size (average value of length and width) of pores in the AQ pin and gear tooth is between 30 and 40 lm.…”

“…By using pinon-disc tests, Wakuda [10] verified the effect of microdimples on the frictional properties of a silicon nitride ceramic on hardened steel and successfully reduced the friction coefficient from 0.12 to 0.10 under lubricated conditions. Using reciprocating sliding of a ball-bearing steel against textured diamond-like carbon (DLC) surfaces, Pettersson [11] showed that under boundary lubrication conditions, some textured DLC surfaces exhibited excellent performance. In pin-on-disc tests, Kovalchenko [12] showed that the beneficial effects of micro-dimples are more pronounced at higher speeds and with higher viscosity oil.…”