The paper presents results of X-ray measurements of the texture of a magnetite (Fe3O4) layer formed on 10CrMo9-10 steel during 100,000 hours operation at the temperature of 575°C (in a flowing medium environment). The formed oxide layer was ≈140µm thick. Measurements of texturing were performed on the oxide surface and also at the depth of ≈50µm from the surface (1st polishing) and ≈100µm (2nd polishing). X-ray studies were carried out using the radiation of a cobalt anode tube, λCo=0.17902nm, for (311) and (400) Fe3O4 reflections, using a radiation beam collimated to φ=2mm. The study was aimed at determination of correlation between the texturing and the structure on the magnetite layer cross-section. A clear texturing of {111} and {111} type for the magnetite in the initial state and after the second polishing was found. Instead, after the first polishing there was a substantial texturing of {034} and {015} type. A different nature of the texture may result from a diversified morphology of magnetite at various depths (caused inter alia by a differentiated temperature on the tube wall cross-section during the material operation), which is related among other things to the crystallites size. The magnetite structure and texture changes can affect the magnetite porosity and cleavage.
Development and Characteristics of the x-ray transmission anode tube for the thickness measurement of film