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Alkaline non-cyanide zinc




2005

I hold very tight parameters with my alkaline zinc tanks except 1 parameter...HEAT. I can not control temp yet. My question is does starter get pushed out by high temps, >90deg?
My current vendor says that the starter is lost by drag-out only. I'm seeing otherwise. When the baths get close to 90deg and maintain that high temp, I have to not only add more brightener to the bath but, also starter to get back my luster, the brightener doesn't do it alone. Every time the tanks get hot I end up using more starter to maintain luster. My deposit ratio also changes as well, from 2:1 to 3.5-4:1. Any thoughts?

JEFF W LENTZ
plating co. - Lancaster, Pennsylvania


A. Dear Jeff

Do you have cooling system in your plating bath. now alkaline cyanide-free baths are running at above 90
to 100 degree (F).check your metal caustic.try to maintain 10 to 12 gm metal and 90 to 110 caustic. check all connection for heat generation. Now additives are available for high temp tolerance. in India we are maintaing temp around 80 to 100 some times 110.the ratio we are getting 2;1
good filtration and periodic carbon treatment and removal of iron from the bath will improve the quality.

p gurumoorthi
P. Gurumoorthi
electroplating process chemicals - Chennai, Tamilnadu, India
2005



2005

Q. Thanks for the response however, it don't quite answer my question. Does high temperatures push out starter? I know you lose brightener when the tanks get hot but does temp also effect starter in the same manner? Also, does the starter serve as an emulsifier for the brightener?
these are my tank parameters
Zinc 1.0-2.0 oz/gl
Sodium Hydroxide 18-19 oz/gl
starter 2%
brightener .25-.75%

I need a clarified answer if heat will push out starter.

JEFF W LENTZ
plating co. - Lancaster, Pennsylvania


A. Different additives for alkaline non cyanide zinc have different temperature limits. Generally the older products work in a range from 55 to 70 °F. Newer products work in the range of 65 to 95 deg. F. While the bath can be operated at higher temperatures generally more brightener will be necessary with a consequent increase in starter if the starter is needed to solubilize the brightener or if they need to be kept in ratio for other reasons. This has to do with entropy. These chemicals are not lost at this temperature but are present in the bath in excess at the lower operating temperatures.

Your supplier is correct when he says starter (also called carrier, generally a quatenary material)is consumed only by drag out. He did omit that it is possible for oils and greases to attach to the material thereby negating its desirable properties and requiring additional replenishment.

Gene Packman
process supplier - Great Neck, New York
2005


thumbs up signThanks Gene,

You clarified it for me. Stop in sometime.

JEFF W LENTZ
plating co. - Lancaster, Pennsylvania
2005




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