A HIGH-TEMPERATURE CORROSION KINETIC-STUDY OF HK-40 SUPERALLOY SURFACE-TREATED, IN CONTACT WITH EUTECTIC MIXTURE 82-PERCENT-K2S2O7-18-PERCENT-V2O5

The corrosion kinetics of the HK-40 superalloy have been studied by el ectrochemical methods in inert and oxidizing atmospheres in contact wi th 82% K2S2O7-18% V2O5 (molar ratio) molten mixture, in order to estab lish the influence of oxygen in the corrosion process. The effect of t he operation temperature and the presence of carbon residues mixed wit h the molten salt mixture is also studied. The effect of different coa ting treatments (coatings of silicon nitride and 25 wt% Al-2(OH)(4)Si2 O5-75 wt% Na2SiO3) have been established in order to analyze their inf luence in the kinetic behaviour. The results with CVD-Si3N4 have been good, but the most promising results corresponded to the new silicate/ kaolin coating. Copyright (C) 1996 Elsevier Science Ltd