My main motive is to separate copper layer adhere over steel rod but same time steel properties should not change.
Hi !
What about the difference of their expansion coefficient? If they are different, putting your sample in liquid nitrogen (77K) will help separating them ?
Cedric
Hi Pankaj,
Aqueous ammonia can selectively dissolve the copper leaving steel rod unaffected. However, you have to try it patiently as the dissolution will depend upon the time and conc. of ammonia and also how you apply this method in the actual way.
-Navneet
dear Navneet
i got Phd from BHU on corrosion +passivation In 1978
CSIR , India may have technologies
i suggest use Hexamine as an inhibitor + try mercapto benzothiazloe in HCl acid
Purpose is you want virgin steel - no passivation
try along with Hexamine and copper complexing tri ethanolamine- try also ETDA adjust pH
Besides nitric acid and aqueous ammonium hydroxide, quite a few other etchants can be also considered for the intended selective etching of copper over steel: solutions of ammonium persulphate or carbonate, the above stated ammonium solutions with added hydrogen peroxide and/or caustic hydroxide (NaOH, KOH), aerated or oxygenated diluted sulphuric acid (5─10% w/w), diluted chromic acid (5─10 % w/w), mixture (~1:2) of chromic acid with sulphuric acid (concentrations as before), solution (~1:2) of hydrogen peroxide (~20 w/v) in sulphuric acid (~ 8─15 % w/w). Etching by the above stated solutions can be enhanced if prepared with aerated or (preferably) with oxygenated water, if ferric chloride is added (to promote pitting), or by adding suitable water soluble amine(s). Concentrated sulphuric acid could also be used, but only with compatible steels.
dear all we want virgin steel polished not pitted - that is needed
Do not try oxidizing acids noFeCl3 solution ---
Why not use the soluble anode method, dip the copper layer adhere over steel rod acting as the anode into dilute copper (ii) sulphate solution. You can put a thin pure copper wire as your cathode. Pass a low current on the electrolyte, copper will dissolve from anode and is collected at the cathode. Since Silver is less reactive than copper it will not react with the electrolyte. As a result pure silver remains at the anode.
Dear jeremiah
we want a simple stripper solution to remove copper layer - a simple solution which can be applied using a brush and should dry quickely
Stripping solutions of copper commercially may be available ; he may want to develop one
Okay, what about this link? "Method of removing copper deposits from ferrous metal surfaces using hydroxyalkyl thiourea", Removal of copper-containing incrustations from ferrous metal surfaces accomplished in improved manner by addition of a hydroxyalkyl thiourea having at least two carbon atoms in the alkyl group such as l-hydroxyethyl-3- methyl thiourea to an aqueous treating solution and subsequent treatment of ferrous metal surfaces wherein reduced sludge formation accompanies removal of copper and the avoidance of copper plating.
http://www.google.com.br/patents/US3579447
Dear Jeremiah Masime,
First of all thanks for your support. Can you explain clearly soluble anode method because in your earlier explanation there are some mistakes of words like pure copper wire as cathode and then you are talking about pure silver at anode.
My main motive is to separate copper layer adhere over steel rod but same time steel properties should not change.
Dear Navneet,
Many many thanks for your suggestion of my problem. I have tried this with Aqueous ammonia it is working successfully as it is removing copper without affecting steel. However, process is very slow I have taken Ammonia:water in 2:1 ratio so there is only 4 mg removal in 24 hour.
Kindly let me know how we can increase the rate of removal of copper.
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