Hockey Sticks (en)

Dead and Gone. More corrosion – less conductivity The correct connection of titanium-clad cop- per bars to the power supply is a constantly recurring issue. It is widely believed that the poor conductivity titanium should be remo- ved from the contact surfaces – usually by milling or turning: On the face of it this approach seems logical. The conductivity of copper is 58 m/⍀ x mm2, while that of titanium amounts to as little as 2,2 m/⍀ x mm2. Thismeansthatacopperwireof1mm2 in diame- ter has a resistance of 1 Ohm. With titanium the same resistance is already reached at a length of 2.2 m. However, reality looks a little different. For example, environmental influences have to be taken into consideration. When cleaned of titanium the copper contact surfaces corrode as a result of their exposure to aggressive acids, vapors and condensates in the galva- nic treatment. The copper at the contact surfaces is eaten away by corrosion. The resulting point contacts at the contact surfaces cause the electrical conductivity to deteriorate. These hockey sticks are so corroded after a short service life that they can no longer be used in this condition. So far people tried to remedy the situation by applying copper solder and subsequently surface milling the contact surfaces to render them usable again. Yet, after a short time of use these repaired hockey sticks are corroded again and depending on their condition are either repaired again or scrapped.

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