Copper Plating

Definition - What does Copper Plating mean?

Copper plating is an electro-chemical process, in which a layer of copper is deposited on the metallic surface of a solid through the use of electric current.

Copper plating is an important process because:

  • It provides valuable corrosion protection.
  • It improves wear resistance of the surface.
  • It has excellent adhesion to most base metals, improving ductility of coated products.
  • It has excellent heat conductivity and electrical conductivity, making the plated products suitable for precision engineering applications, such as printed circuit boards (PCB).

Corrosionpedia explains Copper Plating

Copper is one of the best electrical conductors. A layer of copper offers an excellent electrical conductivity to many components. As a result, copper plating is used in both the electrical as well as electronics industries. As copper is a soft metal, it can be applied to metal parts that require some flexibility. The copper layer won't peel out, as it maintains adhesion to the metal surface, even under bending conditions. It gives a uniform coverage on most non-ferrous and some of the ferrous base metals.

In the process of copper plating, copper sulphate acts as an electrolyte, copper wire dipped in electrolyte works as an anode and an iron rod to be plated is dipped in electrolyte and connected externally as a cathode.

When an electric circuit is switched on and current passes through, the copper sulphate (CuSO4) molecule is split into positive copper ions and negative sulphate (SO4) ions. The positive Cu2 ions are attracted to the cathodic iron rod. When the Cu2 ions reach the cathode, they take 2 electrons, creating neutralized metallic copper, and are then deposited onto the iron rod surface. The copper molecules in the copper anode change to Cu ions, losing 2 electrons. When they enter the electrolyte solution and chemically react with sulphate ions, copper sulphate is produced to re-balance the concentration of the electrolyte.

Copper plating provides excellent wear and corrosion protection of nickel-plated steel parts as an under-coating. As an under-plate it provides an effective barrier between base material and subsequent metal deposits.

Copper plating is applied to fully cleaned as well as pickled steel products, such as steel wire, by the process of electro deposition. The copper layer protects the coated sections against diffusion of carbon or cementation within the sections. Copper plating is also used in protective chrome plating, in which copper forms the intermediate plate. Nickel plating is applied over the copper layer on steel, then a thin coat of chromium is applied for effective corrosion resistance.

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