Influence of Load and Sliding Speed on Friction Coefficient of IBAD ...

Figure 13. Line analysis across the worn channel (Zone2)4. CONCLUSIONSThe tribological properties <strong>of</strong> TiN films preparedby ion beam assisted deposition (IBAD) wereevaluated. Although IBAD is technology whichinfluences the roughness <strong>of</strong> thin films greatly, thedifference between the surface roughness <strong>of</strong> steelsubstrate <strong>and</strong> as-deposited TiN coatings wasnegligible.Change in applied load <strong>and</strong> sliding speedinfluenced the average values <strong>of</strong> frictioncoefficient. Low fluctuation <strong>of</strong> COF was observedwhen sliding with high speeds.The EDS analysis confirmed the presence <strong>of</strong> oxidesat the worn surface. There was no evidence <strong>of</strong>presence <strong>of</strong> aluminum inside wear tracks. It wassupposed that the material transfer from thecorundum ball did not happen because the ball washarder than TiN coating.Atomic force microscopy shows no significantdisturbances, nor smeared debris inside the weartrack, <strong>and</strong> gives the explanation for low values <strong>of</strong>friction coefficient.The depth <strong>and</strong> width <strong>of</strong> wear track increased withincreasing applied load, while COF did not changedsignificantly.Relatively small difference in the COF at differentapplied loads can be explained by differentoxidation <strong>of</strong> contact surfaces, which influencessliding properties <strong>of</strong> contacting surfaces.REFERENCES[1] P.Harlin, P. Carlsson, U. Bexell, M. Olsson:<strong>Influence</strong> <strong>of</strong> surface roughness <strong>of</strong> PVD coatingson tribological performance in sliding contacts,Surface & Coating Technology, Vol. 201,pp.4253-4259, 2006Tribology in industry, Volume 31, No. 3&4, 2009. 9