Hi Dennis,

        We do not typically call the anode film smut, but refer to it simply as
the anode coating (A rose by any other name...). There are a few causes for
loosing the film or coating. One problem is in trying to plate at too high an
anode current density; you should check the anode area as compared to the
Cathode and calculate the anode current density.
Too few anodes or an anode to cathode ratio of less than 2/1 could well be the
problem. Also too many anodes or too great an anode to cathode ratio will
result in not forming a good coating. We found years ago, that if we dummy
plated at about 1/2 the normal cathode current density that we could build a
good coating. A sure sign that you are loosing the coatings is the polarization
of the anode or Current dropping off and Voltage increasing during plating. You
must have some Chlorides in the bath to help build the coating. Different
copper baths, and I am assuming that is what we are discussing, will require
different amounts of chlorides. Typical concentrations are about 50 PPM. This
should be checked after bath make up and/or after Carbon treating and also
after running for a period of time as the new build of the coating will consume
some chlorides.

        I hope these suggestions or of some value. It would be nice to know if
you are using bar anodes or nuggett anodes in a basket. The functional area
calculations are somewhat different.

Lots of luck,

Les Connally

[log in to unmask]

>  From: Dennis Rice <[log in to unmask]>, on 10/9/97 12:14 PM:
>  WE HAVING BEEN HAVING TROUBLE WITH OUR ANODES LOSING SMUT. COULD SOMEONE
>  GIVE ME THE CAUSES WHY THIS COULD HAPPEN WITH A TREATED BATH AND NEW
>  ANODES AFTER DUMMY PLATING. THIS IS AN ON GOING PROBLEM.
>
>  THANKS
>  DENNIS RICE
>
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