Corrosion of aluminides by molten nitrate salt

Conference · Mon Jan 01 04:00:00 EST 1990

OSTI ID:6767438

Tortorelli, P F; Bishop, P S

The corrosion of titanium-, iron-, and nickel-based aluminides by a highly aggressive, oxidizing NaNO{sub 3}(-KNO{sub 3})-Na{sub 2}O{sub 2} has been studied at 650{degree}C. It was shown that weight changes could be used to effectively evaluate corrosion behavior in the subject nitrate salt environments provided these data were combined with salt analyses and microstructural examinations. The studies indicated that the corrosion of relatively resistant aluminides by these nitrate salts proceeded by oxidation and a slow release from an aluminum-rich product layer into the salt at rates lower than that associated with many other types of metallic materials. The overall corrosion process and resulting rate depended on the particular aluminide being exposed. In order to minimize corrosion of nickel or iron aluminides, it was necessary to have aluminum concentrations in excess of 30 at. %. However, even at a concentration of 50 at. % Al, the corrosion resistance of TiAl was inferior to that of Ni{sub 3}Al and Fe{sub 3}Al. At higher aluminum concentrations, iron, nickel, and iron-nickel aluminides exhibited quite similar weight changes, indicative of the principal role of aluminum in controlling the corrosion process in NaNO{sub 3}(-KNO{sub 3})-Na{sub 2}O{sub 2} salts. 20 refs., 5 figs., 3 tabs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOE/CE
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6767438
• Report Number(s): CONF-901008-5; ON: DE91001626
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140700 -- Solar Thermal Power Systems
36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALKALI METAL COMPOUNDS
ALLOYS
ALUMINIUM ALLOYS
CHALCOGENIDES
CHEMICAL REACTIONS
CORROSION
CORROSION RESISTANCE
CORROSIVE EFFECTS
CRYSTAL STRUCTURE
IRON ALLOYS
IRON BASE ALLOYS
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
NITRATES
NITROGEN COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
POTASSIUM NITRATES
SCALING
SODIUM COMPOUNDS
SODIUM NITRATES
SODIUM OXIDES
SOLAR RECEIVERS
TITANIUM ALLOYS
WEIGHT