Hot Corrosion of Nickel-Base Alloys Containing Aluminium and Molybdenum.
Interim scientific rept. no. 2, 15 May 73-14 May 74,
LIVERPOOL UNIV (ENGLAND) DEPT OF METALLURGY AND MATERIALS SCIENCE
Pagination or Media Count:
The effects of pre-sulfidation in H2 - 10 H2S mixtures, where the sulfur activity is sufficient to form nickel and chromium sulfides, on the oxidation behaviour of a series of Ni-Cr, Ni-Cr-Al, Ni-Cr-Mo and Ni-Cr-Al-Mo alloys was investigated. In binary Ni-15Cr alloys the presence of dispersed chromium sulfides in the alloy preclude the formation of a continuous Cr2O3 layer. The presence of malybdenum and to a lesser extent aluminium in the alloy increases the extent of attack after pre-sulfidation, particularly the depth of penetration of internal sulfides. Neither element is particularly deleterious under direct oxidation conditions, at least in flowing atmospheres. The technique of a brief pre-sulfidation treatment followed by oxidation is able to produce corrosion morphologies strikingly similar to those observed in practical hot corrosion conditions and it seems probable that the role of sulfur has been underestimated in recent mechanistic investigations. Author
- Properties of Metals and Alloys