Wear properties of diamond-like carbon coatings with silicon and chromium as adhesion layer using a high frequency reciprocating rig

Abstract

The application of Diamond-like-carbon coatings (DLC) to bearing surfaces is widespread from machining to bio-implants and has resulted in significant study of coating properties. The aim of this investigation was to determine the performance of two diamond-like-carbon coatings, using Chromium and Silicon as adhesion layers. Linear reciprocating wear tests were carried out at room temperature using an AISI 440C steel ball reciprocating against the DLC coated metal substrate. The performance of the coatings under different contact pressures (500 to 3000 MPa); peak sliding velocities (28 to 378 mm/s); and stroke length, (1.5 to 4 mm). An electric resistance measurement was used to monitor coating failure owing to the dielectric nature of the tested coatings.An increase in contact pressure resulted in a decrease in number of cycles to failure for both the coatings. However, the number of cycles to failure increased proportionally with sliding speed. In addition, artifacts on the coating and blister formation generated coating debris which acted as a third body during the wear process. The debris caused complete delamination of the coatings initially at the ends of the wear scar. The Silicon adhesion layer coating samples were found to provide a greater resistance to failure due to it being thicker, harder, and more elastic as compared to samples having a Chromium adhesion layer.

A methodology for characterizing the electrochemical stability of DLC coated interlayers and interfaces

“…Reciprocating wear tests on DLC coated steel demonstrated that samples with a Si interlayer provided greater resistance to delamination failure than samples with Cr interlayers [8].…”

Improving the Tribological Properties of Spark-Anodized Titanium by Magnetron Sputtered Diamond-Like Carbon

“…Taking into account the superior tribological performance of DLC film, it is reasonable to speculate that depositing DLC into the micro-pores of spark-anodized titanium to fabricate a novel TiO 2 /DLC composite coating can provide better wear protection to the titanium substrate. On one hand, the DLC film deposited directly on the titanium surface easily suffered premature failure due to significant difference in mechanical properties of titanium substrate and DLC film [25]. Thus, a transition layer between titanium substrate and DLC film, such as anodic oxide film, helps promote the adhesion of DLC to the substrate [25,26].…”

“…On one hand, the DLC film deposited directly on the titanium surface easily suffered premature failure due to significant difference in mechanical properties of titanium substrate and DLC film [25]. Thus, a transition layer between titanium substrate and DLC film, such as anodic oxide film, helps promote the adhesion of DLC to the substrate [25,26]. On the other hand, introducing DLC material into micro-pores of anodic TiO 2 film can contribute to decreasing surface roughness and porosity of spark-anodized titanium.…”