Studies on the adhesion of oxide layer formed on X10CrMoVNb9-1 steel

The paper contains results of studies on the formation of oxide layers on X10CrMoVNb9-1 (P91) steel long-term operated at an elevated temperature. X10CrMoVNb9-1 steel operated at the temperature of 595 °C for 54,144 h was the studied material. X-ray structural examinations (XRD) were carried out, microscope observations using an optical and scanning microscope were performed. The native material chemical composition was analysed by means of emission spark spectroscopy, while that of oxide layers on a scanning microscope (EDS). Mechanical properties of the oxide layer – steel (substrate) were characterised on the basis of scratch test. The adhesion of oxide layers, friction force, friction coefficient, scratching depth was determined as well as the force at which the layer was delaminated. It has been found that the oxide layer formed under the influence of applied pressure is more degradeted in the areas where are porous and cracks.