Electrochemical corrosion behavior of alloy 400: Intergranular corrosion in acidic Na2SO4 solutions
Description
The influence of heat treatments on the anodic polarization behavior of alloy 400 in acidic Na2SO4 solutions with different pH values and chloride contents has been studied. Alloy 400 is susceptible to intergranular corrosion (IGC) in 0.5 N Na2SO4 solution (pH 3) containing 0.2% CuCl2. For the same heat treatment (soaking for one hour at 900 C), the extent of IGC appears to be significantly affected by the cooling rate, which is greater for faster cooling (e.g., water quenching). Aging the water-quenched alloy at 500 C enhances IGC susceptibility, and aging at higher temperatures imparts resistance to IGC. Note that addition of small amounts of hafnium has a beneficial effect on the resistance to IGC of alloy 400 under similar exposure conditions. An attempt has been made to rationalize the observations in terms of segregation of sulfur and phosphorus to the grain boundaries
Additional details
Publishing Information
- Journal Title
- Corrosion (Houston)
- Journal Volume
- 49
- Journal Issue
- 2
- Journal Page Range
- p. 135-144.
- ISSN
- 0010-9312
- CODEN
- CORRAK
INIS
- Country of Publication
- United States
- Country of Input or Organization
- United States
- INIS RN
- 24071626
- Subject category
- S36: MATERIALS SCIENCE;
- Descriptors DEI
- AGING; AQUEOUS SOLUTIONS; COPPER ALLOYS; COPPER CHLORIDES; ELECTROCHEMISTRY; FEEDWATER HEATERS; GRAIN BOUNDARIES; HAFNIUM; HEAT EXCHANGERS; HEAT TREATMENTS; INTERGRANULAR CORROSION; METALLURGY; NICKEL BASE ALLOYS; PH VALUE; PHOSPHORUS; SODIUM SULFATES; STEAM GENERATORS; SULFUR; TEMPERATURE RANGE 0400-1000 K; TEMPERATURE RANGE 1000-4000 K; TUBES
- Descriptors DEC
- ALKALI METAL COMPOUNDS; ALLOYS; BOILERS; CHEMICAL REACTIONS; CHLORIDES; CHLORINE COMPOUNDS; COPPER COMPOUNDS; COPPER HALIDES; CORROSION; CRYSTAL STRUCTURE; DISPERSIONS; ELEMENTS; HALIDES; HALOGEN COMPOUNDS; HEATERS; HOMOGENEOUS MIXTURES; METALS; MICROSTRUCTURE; MIXTURES; NICKEL ALLOYS; NONMETALS; OXYGEN COMPOUNDS; SODIUM COMPOUNDS; SOLUTIONS; SULFATES; SULFUR COMPOUNDS; TEMPERATURE RANGE; TRANSITION ELEMENT COMPOUNDS; TRANSITION ELEMENTS; VAPOR GENERATORS