Abstract
In the view of the increasing need for applying water cooling to electronic equipment, the corrosion behavior of copper was evaluated in a test loop simulating a water cooling system. Pure water or water containing inhibitor was used as the cooling water in order to maintain reliability of the system. Three conditions of water quality were used in the tests: First, testing water controlled by ion-exchanger (pure water) second, 160ppm benzotriazole (BTA) inhibitor added to the testing water; third, testing water uncontrolled by ion-exchanger or BTA inhibitor. In pure water, the formation of fine CuO film inhibits a corrosion of copper when a flow rate is under 4m/s. The corrosion kinetics follows a parabolic rate law. In the testing water containing BTA inhibitor, the corrosion is inhibited by the formation of fine copper-BTA complex film at a flow rate under 4m/s. The corrosion kinetics follows a logarithmic rate law. In the uncontrolled water, the corrosion is not inhibited because copper dissolves through porous CuO film at a flow rate above 1m/s. Then, the corrosion kinetics follows a linear rate law. It is thus concluded that the corrosion rate increases when the ion exchange resin is degraded or concentration of BTA decreases. Consequently, maintenance of ion exchanger and concentration of BTA are required for a high reliability of the system.
