Effects of lubrication and humidity on the abrasiveness of a thin boron carbide coating

Abstract

Studies using thin boron carbide (B 4 C) coatings have previously been performed in order to investigate their potential use as finite-life run-in coatings. Such coatings have been shown to polish the mating surface in a relatively short time. The inherent ability of these coatings to polish can potentially allow them to function as finite-life run-in coatings. Employing such coatings requires a thorough understanding of the parameters which directly influence the changes that occur in the coating abrasiveness throughout the duration of the polishing process. In past studies, changes in the coating abrasiveness during dry sliding wear under ambient conditions have been investigated. However, both lubrication and humidity can strongly influence the abrasive wear process. In this study, the influences of the operating environment, namely humidity and lubrication, on the coating abrasiveness are directly investigated. The coating abrasiveness decreases at a slower rate when a lubricant is added and when the humidity decreases.

Interaction of DLC and B4C coatings with fully formulated oils in boundary lubrication conditions

“…Although the absence of boric acid prevents further friction reduction in this system, B-O compounds could provide low friction coefficient (around 0.11) in boundary lubrication conditions. The above results are in agreement with the previous report by Siniawski et al [27] which suggested that an evolution of the surface oxidation of the B 4 C coating primarily lead to the reduction in friction coefficient. In terms of wear performance of the Steel/B 4 C system, a large amount of phosphorus which generally plays a significant role as an anti-wear agent at the rubbing surface was detected on the wear scar of the ball in Oil B compared to that in Oil A.…”

“…In-situ Raman analysis revealed the formation of boric acid and carbon at the sliding interface of annealed B 4 C and sapphire and evolution of carbon amount lead to higher friction [26]. In terms of the tribological properties of lubricated B 4 C, Siniawski et al [27] reported that B 4 C coatings lubricated with mineral oil in boundary lubrication condition showed low friction coefficient: around 0.12 compared with unlubricated B 4 C. However, the interaction between B 4 C contact surface and lubricant additives is not fully understood.…”

Wear resistance and microstructure in annealed ultra high molecular weight polyethylenes

“…It was found by Siniawski et al [10][11][12][13] that the average abrasiveness decreased with increasing sliding distance following the power law as…”