Corrosion, stress corrosion cracking, and electrochemistry of the iron and nickel base alloys in caustic environments. Progress report, 1 March 1976--28 February 1977
Stress corrosion cracking (SCC) of Type 304 stainless steel in 20N caustic solution was investigated in the presence of chromate ions, using the constant strain rate (10/sup 7/-10/sup 5//s) technique. Results confirmed that the chromate ions act as an oxidizing inhibitor and prevent caustic cracking. The threshold concentration of chromate was also confirmed to be 0.005M in 20N caustic solution. This chromate concentration was also effective in a mixed caustic-chloride environment of 20N NaOH + 0.1M NaCl. A fast (10/sup -3/-10/sup -1//s) constrant strain rate technique for predicting the SCC acuity of metals was tested with Type 304 stainless steel in 20N NaOH solution. In order to assess the long-term corrosion kinetics of pure nickel in caustic solution, controlled-potential coulometry experiments were done in 10N NaOH at 110/sup 0/C, using several potentials in both the active and the passive regions for over 1000 minutes each. Periodic analysis showed a nickel concentration always considerably lower than expected from the measured coulometric charge, proving the excellent corrosion resistance of nickel in the caustic environment . In fused sodium hydroxide at 350/sup 0/C under four different blanketing atmospheres, nickel was found to have a good corrosion resistance (less than 5 mpy) under all blanketing atmospheres; however, the rate increased with oxidizing condition. The atmospheres in the order of corrosion rate ranked: Air > (Ar + 5 ppM O/sub 2/) > (90% Ar + 10% H/sub 2/) > H/sub 2/. The specimen exposed to caustic under a hydrogen blanket had a shiny surface, whereas the one under the air blanket was covered with a black film of NiO. 10 fig, 4 tables. (DLC)
- Research Organization:
- Ohio State Univ., Columbus (USA). Dept. of Metallurgical Engineering
- DOE Contract Number:
- EY-76-S-02-2421
- OSTI ID:
- 7321888
- Report Number(s):
- COO-2421-03
- Country of Publication:
- United States
- Language:
- English
Similar Records
Inhibitive effect of oxyanions on the stress corrosion cracking of Type 304 stainless steel in boiling 20N NaOH solution
Corrosion, stress corrosion cracking, and electrochemistry of the iron and nickel base alloys in caustic environments. Progress report, 1 March 1977--28 February 1978
Related Subjects
NICKEL
CORROSION
STAINLESS STEEL-304
STRESS CORROSION
AIR
AQUEOUS SOLUTIONS
ARGON
CHEMICAL REACTION KINETICS
CHROMATES
CONTROLLED ATMOSPHERES
CRACKS
HYDROGEN
MOLTEN SALTS
OXYGEN
POTENTIOMETRY
SODIUM CHLORIDES
SODIUM HYDROXIDES
TENSILE PROPERTIES
ALKALI METAL COMPOUNDS
ALLOYS
ATMOSPHERES
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
CHROMIUM ALLOYS
CHROMIUM COMPOUNDS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
CRYOGENIC FLUIDS
DISPERSIONS
ELEMENTS
FLUIDS
GASES
HALIDES
HALOGEN COMPOUNDS
HEAT RESISTING ALLOYS
HYDROGEN COMPOUNDS
HYDROXIDES
IRON ALLOYS
IRON BASE ALLOYS
KINETICS
MECHANICAL PROPERTIES
METALS
MIXTURES
NICKEL ALLOYS
NONMETALS
OXYGEN COMPOUNDS
RARE GASES
REACTION KINETICS
SALTS
SODIUM COMPOUNDS
SOLUTIONS
STAINLESS STEELS
STEELS
TITRATION
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
360105* - Metals & Alloys- Corrosion & Erosion