HIGH-TEMPERATURE CORROSION OF MA 956 IN SULFIDIZING OXIDIZING CARBURIZING ENVIRONMENTS - A STUDY OF THE INFLUENCE OF PREOXIDATION ON THE CORROSION-RESISTANCE OF THE ALLOY
F. Uberti et al., HIGH-TEMPERATURE CORROSION OF MA 956 IN SULFIDIZING OXIDIZING CARBURIZING ENVIRONMENTS - A STUDY OF THE INFLUENCE OF PREOXIDATION ON THE CORROSION-RESISTANCE OF THE ALLOY, Journal de physique. IV, 3(C9), 1993, pp. 197-204
The influence of preoxidation and of the presence of HCl or of char de
posits upon the high temperature corrosion of MA 956 in simulated coal
-gasification environments has been studied at 700-degrees-C for perio
ds up to 2000 h. The corrosion of the blank material produced mixed Al
-Cr sulfide-oxide scales, while preoxidation led to the development of
alumina scales well adherent to the substrate which were quite protec
tive since no sulfide formation was observed even after 1000 h exposur
e to the sulfidizing gases. On the contrary, HCl produced a significan
t enhancement of the corrosion rate of the bare alloy: however, preoxi
dation was able to afford a reasonable degree of protection even in th
is case. Coal chars had little effect on the corrosion in the absence
of HCl.