Ni-Al 系金属間化合物の 75% Na_2SO_4-25% NaCl 溶融塩中における高温腐食挙動

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Hot corrosion behavior of intermetallic compounds NiAl, Ni_3Al, Ni_3(Al, Ti) and NiAl+Cr in a fused 75% Na_2SO_4-25% NaCl salt has been investigated in the temperature range from 700° to 1000℃ in comparison with that of Ni and Ni-base superalloy IN-738LC. The results obtained are as follows : (1) The corrosion loss in weight of Ni_3Al and Ni_3(Al, Ti) is much larger than that of NiAl, Ni and IN-738LC. For NiAl and IN-738LC, the peak of corrosion loss is observed at 800℃. (2) Oxide layers such as α-Al_2O_3 and Cr_2O_3 formed on the surface of NiAl and IN-738LC above 850℃ cause a decrease of corrosion loss. These oxides, however, are not protective completely, and the internal degradation such as oxidation and sulfidation is observed. (3) On the surface of NiAl+(20∿40)% Cr, α-Al_2O_3 forms even at a low temperature (∿700℃) and restrains the permeation of the fused salt especially the sulfur into the specimens so that the corrosion loss and the internal degradation is reduced.
社団法人日本鉄鋼協会の論文
1982-01-01