화학공학소재연구정보센터
Materials Chemistry and Physics, Vol.111, No.2-3, 524-533, 2008
Evaluation of hot corrosion behaviour of HVOF sprayed NiCrAl coating on superalloys at 900 degrees C
In the present investigation, NiCrAl coating was deposited on Ni- and Fe-based superalloy substrates by using high velocity oxy-fuel (HVOF) process to study the hot corrosion behaviour in molten salt (Na2SO4-60% V2O5) environment at 900 degrees C under cyclic conditions. The mass gain measurements were performed after each cycle to establish the kinetics of corrosion using thermogravimetric technique. X-ray diffraction (XRD), scanning electron microscopy/energy dispersive spectroscopic analysis (SEM/EDS) and X-ray mapping techniques were used to analyse the corrosion products. The bare superalloys experienced higher weight gain. The NiCrAl-coated Superni 750 alloy (SN 750) provided a better protection among the coated superalloys investigated. The formation of oxides and spinels of nickel, chromium and aluminum may be contributing better resistance to hot corrosion. (C) 2008 Elsevier B.V. All rights reserved.