Influence of TiO₂ Content on the Behavior of Al₂O₃ Layers Under Cyclic Tribological Loads

The sliding wear behavior of thermally sprayed aluminum oxide is fairly well studied, but little is known about its fretting behavior under cyclic tribological loads. This study investigates the fretting behavior of plasma sprayed alumina and the related influence of TiO₂ additions. Three Al₂O₃-TiO₂ composites are sprayed on steel substrates using commercial powders and the resulting layers are characterized based on hardness, porosity, surface morphology, phase composition, and fretting behavior. The results of the study show that TiO₂ additions reduce microhardness and increase coating toughness. The effect of TiO₂ on fretting behavior and surface wear is assessed after 10, 50, 100, 250, and 500 load cycles based on SEM imaging, friction measurements, and debris formation. Observations and test results are presented and discussed. Paper includes a German-language abstract.