Hot Corrosion of NiCrAlY/(ZrO2-CeO2-Y2O3) Composite Coatings in NaCl-Na2SO4 Molten Salt
The metal/ceramic composite coatings that consisted of (Ni-22Cr-10Al-1Y) and (ZrO2-25CeO2-2.5Y2O3) were prepared by the air plasma spray (APS) method. The as-sprayed coatings consisted of metal-rich and ceramic-rich regions, between which the -Al2O3 oxide stringers existed owing to the oxidation of Al in (Ni-22Cr-10Al-1Y) during APS. The composite coatings were hot corroded at 800 and 900 oC for up to 50 h in 75%NaCl-25%Na2SO4 molten salt. The corrosion products that formed on the coating surface during hot corrosion were mostly dissolved off into the molten salt. The scales that remained on the coating surface consisted primarily of Cr2O3, and a lesser amount of NiO and Al2O3. The corrosion resistance decreased, as not only the test temperature and time but also the amount of metal in the coating increased.
Hyungsun Kim, JianFeng Yang, Tohru Sekino, Masakazu Anpo and Soo Wohn Lee
J. H. Lee and D. B. Lee, "Hot Corrosion of NiCrAlY/(ZrO2-CeO2-Y2O3) Composite Coatings in NaCl-Na2SO4 Molten Salt", Materials Science Forum, Vol. 658, pp. 228-231, 2010