Corrosion phenomena of alloy 625 in aqueous solutions containing sulfuric acid and oxygen under subcritical and supercritical conditions

Conference · Thu Dec 31 04:00:00 EST 1998

OSTI ID:350167

Kritzer, P; Boukis, N; Dinjus, E ^[1]

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1. Forschungszentrum Karlsruhe (Germany)

Corrosion phenomena of alloy 625 pressure tubes were investigated in aqueous solutions containing up to 0.2 mol/kg sulfuric acid and up to 1.44 mol/kg oxygen. Applied maximum temperatures and pressures were 500 C, and 38 MPa, respectively. Corrosion started at temperatures around 150 C with intergranular attack. Above 250 C, the whole surface of the alloy was attacked, shallow pits and deep intergranular attack appeared. This behavior can be explained by transpassive dissolution of the protecting Cr(III) oxide layer and leads to severe material loss. The upper temperature limit of severe corrosion at an experimental pressure of 24 MPa was about 390 C. As temperature was increased further and the density of the solution dropped to low values, only slight corrosion was detected.

• OSTI ID: 350167
• Report Number(s): CONF-980316--
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
36 MATERIALS SCIENCE
CHROMIUM OXIDES
CORROSIVE EFFECTS
INCONEL 625
INTERGRANULAR CORROSION
OXYGEN
PITTING CORROSION
SULFURIC ACID
TEMPERATURE DEPENDENCE
WASTE PROCESSING