Sliding friction and wear behaviors of plasma sprayed aluminum-bronze coating in artificial seawater

Abstract

The friction and wear behaviors of plasma sprayed aluminum–bronze (CuAl) coating sliding against silicon nitride (Si3N4) in artificial seawater were investigated and compared with those in pure water and dry sliding. The morphologies of the worn surfaces were analyzed by three‐dimensional non‐contact surface mapping and scanning electron microscopy. Moreover, chemical states of the tribochemical products of CuAl/Si3N4 in seawater were characterized by X‐ray photoelectron spectroscopy. Results show that the plasma sprayed CuAl coating possessed a specific wear rate (in order of 10−7 mm3/Nm) in seawater more than 600 times smaller than that in dry sliding due to the great alleviation in abrasion wear and splats delamination. Besides, the CuAl/Si3N4 had a friction coefficient of 0.06 in seawater, significantly lower and more stable than those in pure water and dry sliding. The tribochemical products of CuAl/Si3N4 in seawater, which were proved to be silica, alumina, and their hydrates, transformed into a loosened wear‐debris layer under the coagulation effect of the seawater and dominated the excellent lubrication state in artificial seawater. Copyright © 2014 John Wiley & Sons, Ltd.

Tribological behaviors of graphite sliding against cemented carbide in CaCl2solution

“…In addition, those inorganic salt solutions are strong electrolytes, so the corrosion rate of alloy steels in seawater is much larger than in pure water, indicating that the tribological condition of the interface in seawater is worse. However, many authors found that the friction coefficient of many materials in seawater was lower than in pure water; even the wear rate of some materials also followed the rule [16][17][18][19]. In our experiment, we also found the friction coefficient between the graphite and cemented carbide was lower than in pure water.…”

“…Lancaster thought that the lower wear rate was attributed to the increased corrosiveness in seawater, which was beneficial to polish the surface and reduce the roughness. Yang et al [16] and Ding et al [17] thought that the lower friction coefficient in seawater was due to the chloride and sulfide of the interface acting as a lubrication film, caused by the tribochemical reaction among chloride ions, sulfate ions, and material surfaces. However, both Wang et al [18] and Chen et al [19] found that when the artificial seawater did not contain divalent cations, such as Ca 2+ , Mg 2+ , etc, the friction coefficient did not obviously decrease in comparison with pure water, so they thought the most important factor was the effect of the Ca 2+ and Mg 2+ .…”

Unexpected friction behaviours due to capillary and adhesion effects

“…Not only that, some special materials’ friction interface can even achieve superlubricity (a friction coefficient of less than 0.01) in a dry environment, but when there is only small amounts of water in the friction interface, the friction coefficient will increase to a significant extent 8 – 11 . More surprisingly, the friction coefficient of a super-hydrophilic poly(MPC) brush sliding against a glass ball probe in water ( i.e ., when the contact interface was immersed in water) was larger than that in normal ambient condition 12 , which was also found for an aluminium-bronze coating sliding against silicon nitride 13 . However, these authors did not propose an effective mechanism by which to interpret this unique frictional property.…”

A study on the tribological behavior of hybrid and all-steel rough sliding contacts

“…12 He et al 13 carried out the performance test of the 9Cr18Mo-steel hybrid pair and analyzed the wear surface morphology, friction coefficient and Vickers hardness of the 9Cr18Mo by Nanovea three-dimensional profiler and metallographic microscope. Yang et al 14 studied the sliding friction and wear behavior of the plasma-sprayed aluminum-bronze coating and Si 3 N 4 , and analyzed the morphological characteristics of the worn surface by 3D non-contact surface mapping and scanning electron microscope. Tian et al 15 used the Laser Scanning Confocal Microscopy (LSCM) to obtain the 3D wear particle images and quantitatively characterized the changes in the surface morphology and wear characteristics.…”