4,160,000 Yen
(Direct Cost: 3,200,000 Yen Indirect Cost: 960,000 Yen)
Research Abstract
Potentiostatically polarized tests of copper tubes in copper formate solution were conducted to investigate the corrosion behavior of pure copper by using electrochemical method. Three kings of copper tubes were used as a specimen; oxygen free copper(OFC) without phosphorous, phosphorous deoxidized copper(PDC) with about 0.02% phosphorous and highly corrosion-resistant copper contains 0.2-0.3% phosphorous.
It takes about one month to generate the corrosion by the immersion test. However, it is possible to reproduce the corrosion for one day by the potentiostatically polarized tests. It is found that the corrosion morphology depends on the phosphorous contents. Ant nest corrosion with branched micropits occurred in the OFC and PDC tubes, while hemispherical pits occurred in the highly corrosion-resistant copper tubes.
