Dissolution Behavior of SUS304 Stainless Steel due to General Corrosion in H{sub}2SO{sub}4-NaCl Aqueous Solution

摘要

In this experiment, three kinds of sintered SUS304 stainless steels (P/M stainless steels) whose porosity ratios were 17.06 (compressed at 392MPa), 11.78 (compressed at 588 MPa) and 8.75% (compressed at 784 MPa) were used. The dissolution behavior of these sintered SUS304 stainless steels in the aqueous solution composed of H{sub}2SO{sub}4 and NaCl were examined compared with that of the conventionally processed SUS304 stainless steel (I/M specimen). All of the P/M SUS304 specimens showed almost linear increment of corrosion mass loss against reaction time and the specimen with higher porosity ratio showed more mass loss, while the I/M specimen showed evidently much less mass loss than any P/M specimens. The reactivation ratio for the P/M SUS304 specimen was higher than the I/M SUS304 specimen and it increased almost linearly with increasing porosity ratio. In the case of 72 ks of reaction time, the charge transfer resistance, Rct, is highest in the specimen compressed at 785 MPa, while it is lowest in the P/M specimen compressed at 392MPa. In the longer region than 144ks, all of the three P/M specimens show the almost constant Rct value of 200 Ω. These Rct tendencies well correspond to the time dependence curve of mass loss.