Evaluation of Corrosion of Boiler Materials in Simulated Boiler Lay-up Waters, Using Electrochemical Corrosion Potential Methods

概要

論文の詳細を見る
The applicability of the electrochemical corrosion potential (ECP) method to the boiler equipment during the long-term shutdown and lay-up units was experimentally investigated for three boiler equipment materials. It is found that the ECPs of all materials show stable values in a few hundred hours after the test, and that oxide films formed in the simulated AVT and CWT waters show a good stability in the following ECP measurement. Under conditions of the coexistence of Cl- and dissolved oxygen, the corrosion potential of the STB 410 carbon steel shifts to the less noble side showing the severe corrosion, although that of the SUS 304 steel is shifted to the noble side showing the high corrosion resistance. The results obtained by the ECP method have the good correspondence with those of the corrosion immersion test. The temporary decrease of the corrosion potential due to the addition of hydrazine to the waters may be resulted from both effects of the reducing reaction of oxide films and the decomposition of hydrazine. From the fundamental results obtained, it is clear that the corrosion of boiler equipment materials during the lay-up period could be detected by ECP method.
社団法人腐食防食協会の論文