Effect of Superficially applied Oxides on the Hot Corrosion behaviour of Fe- and Ni- base Superalloys in Na_2SO_4-60 percent V_2O_5

摘要

In the present investigation the hot corrosion behaviour of two superalloys Superfer 800H (Fe-32Ni-21Cr-1.5Mn-1.0Si-0.3Ti & Al) and Superni 75 (Ni-3.0Fe-19Cr-0.3Ti) has been studied in the most aggressive environment of Na_2SO_4-60 percent V_2O_5 after applying on surface a coating of CeO_2, Y_2O_3 and SnO_2. Thermogravimetry, XRD, EPMA and SEM/EDAX analysis has been carried out to analyze the reaction products and estimate the effect of oxides. Comparison has been made between the coated and uncoated specimens in Na_2SO_4-60 percent V_2O_5 environment. Extent of corrosion of both Fe- and Ni-base alloys reduced by the application of CeO_2, Y_2O_3 and SnO_2.