CORROSION RESEARCH ROUND‐UP

GERMANY Corrosion‐chemico behaviour of reducing waters. Natural waters whose oxygen content has been partly or completely removed by permeating through earth layers, which have a reducing action, can form no natural coatings. They therefore have a progressive dissolving action on any iron with which they come in contact and the water itself after long contact becomes ‘ironised,’ absorbing so much iron that it can no longer be used for drinking or other purposes without treatment. Also, iron surfaces which come in contact with reducing water are relatively quickly destroyed. The speed of destruction varies with different types of iron and steel. Wrought iron on unprotected iron filter tubes is only noticeably destroyed after several decades, but with cast iron the corrosive effect is much more rapid, particularly if the water, besides lacking oxygen, has a high salt content, because then the iron‐dissolving action of the reducing water is strengthened by increased conductivity.