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Tarnishing of copper plated parts

2005

Hello
I have a doubt about tarnishing of copper plated parts. Plated from cyanide bath(Metallic cu-35 gms/lit, Free cyanide-25 gms/lit (KCN)),chromic acid dipped,polished with soap water,final dip in de-ionised water and anti tarnish dip found brownish colour change on keeping (with in 2-3 days). What to do, please.....

Jose K G
- Cochin, Kerala, India

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Mr.Jose

Use of anti tarnish is better.When you use antitarnish no need of chromic acid. try to introduce temperature to antitarnish and good rinses in between plating and antitarnish will solve your problem.

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

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Hi Jose,

Use 20 gpl of Sodium Dichromate for a minutes rinse in slightly warm water, it will work for your purpose.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

2005

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Hi,

Please go for an acrylic or poly - urthane spray or dip lacquer if you really want to resist of tarnishing problem for a very long time........for your information now many suppliers hav chrome free antitarnish even chemisorption antoitarnish can be used which is used for silver protection can be also used , but seems to be little costly.

Regards,

Praveen Kumar
plating process supplier
Mumbai, India
2005

adv.