低濃度亜硝酸塩環境における銅合金の応力腐食割れ感受性
2003 年 52 巻 7 号 p. 358-363
詳細
2003 年 52 巻 7 号 p. 358-363
The stress corrosion cracking (SCC) susceptibility of copper alloys in dilute NaNO2 has been investigated using slow strain rate test (SSRT), constant load test and electrochemical measurement. The SCC susceptibility examination in ammonia environment was also performed.
As a result, aluminum brass showed high SCC susceptibility in low concentration of NaNO2 about 100ppm. The addition of the ammonium ion, which was reported to enhance SCC susceptibility, revealed to reduce the SCC susceptibility. The cause of increase in SCC susceptibility was attributed to the characteristics of nitrite ion. Addition of benzotriazole (BTA), which is widely used to reduce general corrosion, was studied to find the effectiveness of BTA as an inhibitor of SCC in NaNO2 solutions. The formation of protective film, which controls an anode reaction, was attributed to the inhibition of the SCC.
