Behaviour of galvanic couples of copper alloys in synthetic seawater with benzimidazole-2-thiol

✍ Scribed by F. Zucchi; G. Brunoro; M. Zucchini

• Book ID: 103906446
• Publisher: Elsevier Science
• Year: 1978
• Weight: 378 KB
• Volume: 3
• Category: Article
• ISSN: 0390-6035
• DOI: 10.1016/0390-6035(78)90053-6

✦ Synopsis

Admiralty brass (Cu Zn 29 Sn 1) has been coupled to Cu, Cu Zn22 A1 2, Cu AI 7, Cu Ni 10 Fe 1/2, Cu Ni 30 Fe 0.4/1, Cu Ni 30 Fe 2 Mn 2 and tubular specimens of the coupled materials have been inserted in an experimental loop.

The behaviour of the couples in flowing ASTM seawater at 30°C has been studied, both in uninhibited condition and in the presence of Benzimidazole-2thiol (BIE) at different concentrations.

The efficiency of a surface film, grown in a flowing solution of 10 -3 M BIE in distilled water, in reducing the galvanic effect has been tested, too.

Weight loss, galvanic potential and galvanic current measurements have been carried out in ten day tests.

As regards to free corrosion condition, the corrosion rate of Cu Zn 29 Sn 1 is more than twice when coupled to Cupronickel alloys; it considerably increases when coupled to Cu Zn 22 A1 2 and to Cu A1 7; it slightly reduces when coupled to Cu. lO'3M BIE shows a good inhibitor efficiency on all the tested materials, both in free corrosion and in coupling condition.

It comes out, too, that the prefilming treatment is an efficacious practice in reducing the corrosive attack on the coupled and uncoupled materials, also when put in seawater containing very small quantities of the inhibitor (10-SM).