Plasma sprayed (PS) ceramic coatings have found widespread commercial use, particularly for wear resistant surfaces. Understanding of the micromechanical basis of macroscopic weight loss through wear is very important for the development of improved coatings and better uses for existing coatings. This paper aims to elucidate the wear mechanisms that occur when a PS ceramic coating is in sliding contact with a harder asperity, using controlled scratch testing as a model abrasion test. It attempts to relate the scratch test results to the microstructural integrity, or cohesion, of the various coatings. Paper includes a German-language abstract.