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Effects of high temperature surface oxides on room temperature aqueous corrosion and environmental embrittlement of iron aluminides

Technical Report ·
DOI:https://doi.org/10.2172/415344· OSTI ID:415344

Studies were conducted to determine the effects of high-temperature surface oxides, produced during thermomechanical processing, heat treatment (750 {degrees}C in air, one hour) or simulated in-service-type oxidation (1000{degrees}C in air, 24 hours) on the room-temperature aqueous-corrosion and environmental-embrittlement characteristics of iron aluminides. Materials evaluated included the Fe{sub 3}Al-based iron aluminides, FA-84, FA-129, FAL and FAL-Mo, a FeAl-based iron aluminide, FA-385, and a disordered low-aluminum Fe-Al alloy, FAPY. Tests were performed in a mild acid-chloride solution to simulate aggressive atmospheric corrosion. Cyclic-anodic-polarization tests were employed to evaluate resistances to localized aqueous corrosion. The high-temperature oxide surfaces consistently produced detrimental results relative to mechanically or chemically cleaned surfaces. Specifically, the pitting corrosion resistances were much lower for the as-processed and 750{degrees} C surfaces, relative to the cleaned surfaces, for FA-84, FA-129, FAL-Mo, FA-385 and FAPY. Furthermore, the pitting corrosion resistances were much lower for the 1000{degrees}C surfaces, relative to cleaned surfaces, for FA-129, FAL and FAL-Mo.

Research Organization:
Oak Ridge National Lab., TN (United States); Tennessee Univ., Knoxville, TN (United States)
Sponsoring Organization:
USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
DOE Contract Number:
AC05-96OR22464
OSTI ID:
415344
Report Number(s):
ORNL/Sub--88-07685CT92/05; ON: DE97050496
Country of Publication:
United States
Language:
English