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Corrosion behaviour of Ni 3 Al alloys in SO 2 ‐containing combustion gases
Author(s) -
Forsén O.,
Kaskiala M.,
Tikkanen M. H.,
Tavi M.
Publication year - 1990
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.19900411209
Subject(s) - corrosion , materials science , aluminide , metallurgy , nickel aluminide , nickel , sulfidation , high temperature corrosion , zirconium dioxide , zirconium , aluminium , oxide , sulfur , layer (electronics) , intermetallic , composite material , alloy , nial
The high temperature corrosion behaviour of some nickel aluminides alloyed with zirconium or hafnium is presented. The corrosion tests were carried out in the temperature range 920 to 1010°C, both in air and in atmospheres containing sulphur dioxide, using a thermobalance. The results obtained in air show that all the nickel aluminides display sufficient corrosion resistance up to 920°C. Nickel aluminide alloyed with hafnium is more resistant than the aluminide alloyed with zirconium. The oxide layer on the specimens tested in air is always very thin, exhibits low porosity and consists mainly of Al 2 O 3 . Without controlled preoxidation these materials are rather susceptible to corrosion in atmospheres containing sulphur dioxide. The preoxidation in gas mixture containing water vapor and hydrogen markedly improves the corrosion resistance of these alloys. The corrosion implies the selective oxidation of nickel aluminides. The protective layer consists mainly of aluminium oxide and protects the base material also in atmospheres containing sulphur dioxide.