The evaluation of oxide scale formation during hot corrosion of Rene-80 superalloy under thermal shock at different dwell times

Abstract

In this study, the oxide scale formation on the Rene-80 superalloy after hot corrosion under thermal shock has been investigated. The X-ray diffraction (XRD) and field-emission scanning electron microscope (FE-SEM) were used for the phase identification and evaluation of oxide scale, respectively. The hot corrosion test under thermal shock was performed by depositing Na₂SO₄ salt at the beginning of each cycle on the surface of the specimens. The results showed that hot corrosion occurred intermittently with the basic fluxing mechanism of the oxide scale and re-precipitation of discontinuous and porous oxides. The growth rate of the Cr₂O₃ layer increased with decreasing the dwell time per cycle and the dissolution of titanium. Decreasing the dwell time in each hot corrosion cycle increased the growth rate of the Cr₂O₃ layer, the chromium depletion from the substrate/oxide scale interface, the internal oxidation of aluminium, and the internal sulfidation of chromium.