Evaluation of High-Temperature Corrosion on 16Mo3 Steel Long-Term Operated at an Elevated Temperature

Abstract

The paper contains results of studies on the formation of oxide layers on steel long-term operated at an elevated temperature. The oxide layer was studied on a surface and a cross-section at the inner surface of the tube wall. Thorough examinations of the oxide layer carried out on the inside surface of tube wall comprised:microscopic examinations of the oxide layer were performed using an Olympus GX41 optical microscope,thickness measurements of formed oxide layers,chemical composition analysis of deposits/oxides using a Joel JSM-6610LV scanning electron microscope (SEM) working with an Oxford EDS electron microprobe X-ray analyser,X-ray (XRD) measurements; the layer was subject to measurements using a Seifert 3003T/T X-ray diffractometer and the radiation originating from a tube with a cobalt anode (λCo=0.17902 nm). X-ray studies were performed, comprising measurements in a symmetric Bragg-Brentano geometry (XRD). XRD measurements were performed in the 15÷120° range of angles with an angular step of 0.1° and the exposure time of 4 s. To interpret the results the diffractograms were described by a Pseudo Voight curve using the Analyze software. DHN PDS and PDF4+2009 computer software and crystallographic database were used for the phase identification.