Effect of boron on the hot corrosion resistance of sprayed Fe40Al intermetallics

Abstract

The corrosion resistance of three Fe40Al+10Al2O3based sprayed intermetallic alloys with different boron contents in molten sodium sulfate (Na2SO4) and sodium metavanadate (NaVO 3) has been evaluated using the weight loss technique. Boron content was 0.1 (at.%), 0.2 and 0.4 and the temperature varied from 873 K to 973 K for NaVO3, and from 1173 K to 1273 K for Na2SO4 at 25 K intervals. The tests were also supported by electronic scanning microscopy and microanalysis. In all cases, less corrosion resistance was obtained in the alloy with 0.4 B, whereas good corrosion resistance was found in the alloy with 0.1 B. The results were discussed in terms of dissolution of the external Al2O3 layer by the salt and internal sulfidation.