The Hot Corrosion of High-Temperature Nickel-Base Alloys for Marine Gas Turbine Engines

The hot corrosion of high-temperature nickel-base alloys for marine gas turbine engines

Yevgeny E.L. Sanchugov, University Hanover, FUN, section Institute of Mechanic Dynamic, Hanover, Germany

In the present work we studied the hot corrosion resistance of nickel-base superalloys ChS91VI and EP708 for stator parts of marine gas turbine engines is investigated. The corrosion resistance of the alloys to hot (salt) corrosion was determined by the method of semisubmersion into crucibles with molten salts (90% Na₂SO₄ + 10% NaCl). It is shown, that the hot corrosion resistance of superalloys ChS91VI and EP708 are defined at 700^îC in the main by their grain boundaries structure. An x-ray diffraction analysis of corrosion products at 800^îC showed the presence of metal particles and Ni ₃S ₂ in all the alloys. The products of corrosion in ChS91VI also contained a certain amount of NiO× Cr ₂O ₃  spinel, Cr ₂O _{3 ,}Fe ₂O _{3 .}

Thus, the hot corrosion resistance ChS91VI and EP708 are defined at 700^îC in the main by their grain boundaries structure and the catastrophic corrosion fracture occurs at 800^îC

Keywords: high-temperature alloys, nickel, hot (salt) corrosion, corrosion products, gas-turbine