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- Electroplating Objective
Objects are electroplated to
prevent corrosion, to obtain a hard surface or attractive finish, to
purify metals (as in the electrorefining of copper), to separate metals
for quantitative analysis
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- anode out of copper and
- spoon as the cathode.
- The electrodes are placed in an
aqueous solution of CuSO4 and a battery pumps electrons from
anode to cathode.
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- an anode (positively charged electrode), which is the source of the
material to be deposited
- a cathode which is the substrate (the negatively charged electrode) to
be coated.
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- Plating is an oxidation-reduction reaction, where one material gives up
electrons (gets oxidized) and the other material gains electrons (gets
reduced). The anode is the electrode at which oxidation occurs, and the
cathode is the electrode at which reduction occurs.
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- Plating is governed by Faraday's Laws that state:
- 1. The weight of a substance formed at an electrode is
proportional to the amount of current passed through the cell.
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- The object to be coated is placed in a solution, called a bath, of a
salt of the coating metal, and is connected to the negative terminal of
an external source of electricity
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- and to give them an attractive finish
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- Also known as electroless plating
- is a plating process which
involves deposition without any current applied.
- The process is a chemical reaction and is autocatalytic.
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- The technique of fusing electrodeposited tin alloy coatings was
originally used by the U.S.
- aerospace industry on circuit
boards
- and has been increasingly applied
to the production of high-quality printed circuit assemblies in
automotive and other industries.
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