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The present research describes a study to explore the possibility to improve the wear resistance by healing microcracks that initiated under fretting wear. To this aim Ti 3 SiC 2 coatings prepared at different plasma powers (33 and 34 kW) were investigated comparatively under fretting. The results showed that the amount of Ti 3 SiC 2 phases was higher at the lower plasma power, leading to a major difference on fretting wear properties. Coatings with a higher content of Ti 3 SiC 2 phases exhibited a remarkable decrease in the friction coefficient and an enhancement in the wear resistance. The enhanced wear resistance was mainly attributed to the healed cracks by selective oxidation of Ti 3 SiC 2 . The reduced friction coefficient was strongly related to the formation of tribo-induced oxides. [ABSTRACT FROM AUTHOR]

Many wear failures are caused by a combination of fretting wear and sliding wear. In this study, the torsional fretting and torsional sliding wear properties of CuNiAl against 42CrMo4 were comparatively investigated under dry condition using a flat on flat contact tester. Experimental results showed that the sliding friction coefficients declined more dramatically than the fretting friction coefficients when the normal load increased. The fretting wear rate was lower than the sliding wear rate, which was partly due to the solid lubrication effect of the wear debris and strain hardening of the worn surfaces. The dominant wear mechanisms for the fretting tests were oxidation, cracks and delamination, while for the sliding tests were abrasion combined with plastic deformation. [ABSTRACT FROM AUTHOR]

Torsional fretting and torsional sliding wear behaviors of CuNiAl against 42CrMo4 were comparatively investigated in oil, filtered water and artificial seawater. Most experiment parameters except the angular displacement amplitude were set the same for all the tests. Compared with sliding tests, the averaged fretting friction torque of fretting tests tended to be higher but the wear rate was much lower, resulting from the influence of wear trace roughness, lubricant penetration behavior, surface strain hardening and third body effect. The fretting and sliding wear traces were mainly characterized by abrasion. The fretting wear traces under the filtered water and artificial seawater lubrications were also scattered with cracks and delamination, resulting from the frequent shear stress and poorer lubrication condition. [ABSTRACT FROM AUTHOR]