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Preparation of copper plating bath

2004

Dear sir,

I intend to plate a ceramic substrate (alfa alumina) -already electrolessly plated with palladium- with copper. The copper plating bath's constituents are as follows:

1- Copper(II)sulphate Pentahydrate
2- ethylenediaminetetraacetic acid ⇦ this on eBay or Amazon [affil links] , Disodium salt Dihydrate
3- formaldehyde (37%)
4- sodium hydroxide
5- triton X-100
6- 2,2-bipyridyl

My query, is there a particular sequence of mixing these? In other words, which is first mixed with which and which is last? When I plated my substrate with palladium I added hydrazine incrementally. Is the case similar here? and if so which chemical is that

James Smith
hobbyist - Manchester, Lancashire, United Kingdom

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Dear Mr. Smith,

Copper(II)sulphate Pentahydrate is the source of copper, 2- ethylenediaminetetraacetic acid Disodium salt Dihydrate is the complexing agent, formaldehyde is the reducing agent, triton X-100 is a surface active agent.

The order of addition is as follows:

First you add the copper sulphate, then you add the ethylenediaminetetracetic acid salt. Add a portion of deionized water. Make sure that the copper salt is completely dissolved. After this you add the additives and sodium hydroxide. Adjust the pH to the required level. It is preferable to add formaldehyde just before plating.

T.S.N. Sankara Narayanan
- Chennai, Tamilnadu, India
(ed.note: The good doctor offers a fascinating blog, "Advancement in Science" )
2005