Corrosion of steels in absorption heating and refrigeration fluid

Book · Fri Dec 01 04:00:00 EST 1995

OSTI ID:128624

Kojima, Y; Tsujikawa, S ^[1]

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1. Univ. of Tokyo (Japan)

Pitting corrosion of carbon steel and crevice corrosion of Type 304 stainless steel in a newly developed working fluid for absorption heating and refrigeration systems were studied. The fluid was a concentrated aqueous solution of mixed lithium salts consisting of LiBr, LiCl, LiI and LiNO{sub 3}. This solution contained NO{sub 3}{sup {minus}} and a small amount of I{sub 2}, the oxidized species of I{sup {minus}}, both of which were able to act as the oxidizing agent for steels. The spontaneous electrode potential of Platinum, E{sub SP}(Pt), in the 60% solution kept at 150 C was +120 mV vs SCE, and when the I{sub 2} was reduced by the addition of NaHSO{sub 3} the E{sub SP}(Pt) was approximately {minus}120 mV. Thus, the fluid forms an oxidizing halide environment that tends to induce localized corrosion on steels. The critical pitting potential, V{sub C, PIT}, of the carbon steel and the critical crevice corrosion potential, E{sub R, CREV}, of Type 304 stainless steel were measured to be {minus}340 {approximately} {minus}310 mV and {minus}180 {approximately} {minus}160 mV respectively. It became apparent that in solutions containing I{sub 2}, the E{sub SP}`s of the steels were nobler than the critical potentials, and that pitting corrosion of carbon steel and crevice corrosion of Type 304 stainless steel occurred violently. However, it became also apparent that both localized corrosions ceased when I{sub 2} was reduced by adding NaHSO{sub 3}. Resistance of the steels to localized corrosion increased with higher concentration of NaHSO{sub 3} and less concentration of NO{sub 3}{sup {minus}}.

• OSTI ID: 128624
• Report Number(s): CONF-950304--
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
36 MATERIALS SCIENCE
AQUEOUS SOLUTIONS
CARBON STEELS
COOLING SYSTEMS
CORROSION
CREVICE CORROSION
CURRENT DENSITY
ELECTRIC POTENTIAL
ELECTROCHEMICAL CELLS
EXPERIMENTAL DATA
HEATING SYSTEMS
LITHIUM BROMIDES
LITHIUM CHLORIDES
LITHIUM IODIDES
LITHIUM NITRATES
PITTING CORROSION
STAINLESS STEEL-304
TIME DEPENDENCE