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Letter 41040 A couple of questions about Woods Nickel Strike [Canada]June 7, 2006 1. What is the best ratio of anode and cathode surface in Woods
nickel strike tank in order to reduce consumption of nickel? Yongzhong Liao
First of two simultaneous responses -- June 9, 2006 In a Woods bath nickel concentration and pH will tend to rise do to the extremely low (and desirable) eficiency of this bath. This means that far more hydrogen ions than nickel ions are reduced onto the cathode surface. On the anode, the situation is the opposite. More nickel ions are dissolved than required. Hydrogen ions need to be replenished by additions of HCl. Use a 1:1 ratio. Now, if you dummy with insoluable cathode, evolution of dangerous chlorine gas to the ambient results. Guillermo Marrufo
Second of two simultaneous responses -- June 9, 2006 The best ratio I have found is a 3:1 anode to cathode. In plating
the rule of thumb is a minimum of 2:1. Carbon anodes are cheaper than
Ti but you will generate some chlorine at the anode. In dummy plating
you are still going to plate out Ni whether it be from the solution
(Ni chloride) or from the anode. In a woods Ni strike the Ni metal
concentration increases in the bath over time when Ni anodes are used
anyway. If you want to dummy plate to remove excess Ni, insoluble
anodes would make sense. If you just want to try to remove unwanted
metallics and your Ni chloride is in range, using insoluble anodes
would mean analyzing and adjusting the Ni metal after each dummy
plate. If you figure labor time switching out anodes, analysis, adds,
are you really saving money? Mark Baker
June 16, 2006 Thank you all for the information and suggestion. Yongzhong Liao
Dear Reader: please choose what you want to do--
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