Effect of Boron on the Hot Corrosion Resistance of Sprayed Fe40Al Intermetallics

摘要

The corrosion resistance of three Fe40Al+10Al_2O_3-based 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. percent), 0.2 and 0.4 and the temperature varied from 873 K to 973 K for NaVQ3, and from 1173 K to 1273 K for Na_2SO_4 at 25 K intervals. The tests were also supported by electronic scanning microscopy and microanaiysis. 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 Al_2O_3 layer by the salt and internal sulfidation.