ホスホン酸をインヒビターとして含む水溶液中における銅の孔食について

抄録

The pitting corrosion of copper in cold water containing inhibitors composed of amino trimethylene phosphonic acid (ATMP), benzotriazole (BTA) and zinc sulfate (ZnSO₄) has been studied by the immersion test and electrochemical measurements. The results obtained are summarized as follows: 1) the pitting corrosion of copper did not occur in cold water containing ATMP, ATMP+BTA and ATMP+ZnSO₄, respectively. Pitting occurred in cold water containing both ATMP+BTA+ZnSO₄ and ATMP+BTA+Na₂SO₄. The pH value of water lowered to 3. The presence of SO₄^2- in ATMP+BTA solution is essential for the occurrence of pitting corrosion in copper. 2) In the immersion test, pitting corrosion of copper occurred under the presence of SO₄^2- more than 0.6ppm in ATMP+BTA solution. 3) The pitting corrosion easily occurred and the number of pits increased, corrosion potential and breakdown potential became less noble with increase in SO₄^2- concentration from 0 to 180ppm.