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Chrome plating problems, analysis of bath

what are the method of analysis of chrome plating bath?
I am doing decorative chrome plating and my rejection of chrome plating bath is high, how can I control it?

Khan Umair
electro plater - Lahore, Pakistan
October 20, 2010

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Hi, Khan. I hate to say "read a book", but if you give us no starting point, I almost don't know what else to say. What is the target composition of your plating bath, what current and temperature are you using, what kind of defects are you getting? Are the defects at the top of the rack, the bottom, the HCD areas, the LCD areas or where? If you strip the chrome, is the underlying nickel plated part perfect in all respects? Thanks!

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 20, 2010

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Hi,

If your bath is hexavalent chromium, you need to control the concentration of hexavalent chromium and sulfuric acid, and also the current density and racks project. Some contaminants like chloride compounds are very harmful. You have to rinse and activate the parts very well before the chrome bath to have good results.

Regards.

Estacio Filho
- Joinville, SC, Brazil
October 20, 2010

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Sir,
Current density we are using is 25-30 A/dm2,Concentration is 200 g/liter,temperature is 45-50 C, time is 30 second and problem is on LOC area. there is yellowish shade appear in LOC area. some time it increases too much.

Khan Umair
- Lahore, Pakistan
December 9, 2010

You fail to mention the sulphate concentration--That is critical to keep the ratio in a correct range. For me, your temperature is low. I would expect soft or milky areas on your part. Amps per sq dm does not mean much without anode to cathode distance. The greater the distance, the more the amps generate heat. 30 second of plate time probably will not put color on all areas of the part. James Watts - Navarre, Florida December 10, 2010 Dear Khan, Are you plating big parts? your Current Density was too high for me. Try to increase plating time, and check the sulphate content in the Chrome plating bath. Too high sulphate content will reduce the throwing power of Chrome plating. And also consult your chemical supplier, the additives of the Chrome may help to increase Chrome throwing power as well. Eng Chong Lim - Malaysia December 11, 2010