Characterisation of ZrO2 layers deposited on Al2O3 coating

Abstract The paper describes a method of coating combining two different layer types. The first layer is Al 2 O 3 produced by plasma spraying with a thickness of around 200 μm which was deposited on a stainless steel substrate. Subsequently, ZrO 2 layers were deposited on to the Al 2 O 3 coating by a sol–gel process using a dip coating technique. The dip coating process was repeated in order to see the influence of the number of ZrO 2 layers. Moreover, the effect of annealing temperature was investigated. In order to study their tribological behaviour, the coatings were subjected to micro-scale abrasion, scratch testing and ball-on-disc tests. The result shows that sol–gel ZrO 2 top layers reduce friction and enhance the wear resistance of the coating system.