Electroplating is the method of coating objects with a thin film of another metal. The principle governing this phenomenon is electrolysis, whose name comes from two radicals, electro which refers to electricity and lysis which means breakdown.
Electroplating involves the reduction (decrease in oxidation state; gain of electrons) of a metallic compound dissolved in water and a deposition of the resulting metal on a conductive surface.
This technique is probably one of the most complex processes known, because there are a large number of phenomena and variables involved in the overall process, which are carried out on the surface of the materials involved.
In the electrodeposition of metals, the success of the operation depends on the control of the phenomena involved, so it is necessary to mention the principles to which these are subject, since any variation in the process will be reflected significantly in the result obtained.
What is electrochemistry?
Electrochemistry is the science that studies the exchange of chemical and electrical energy produced by an oxidation-reduction reaction.
Oxidation is the loss of electrons, while reduction is the gain of electrons. Oxidation-reduction (redox) reactions are those in which there is a transfer of one or more electrons.
Electrolysis is the name given to the process by which electrical energy is used to produce chemical changes; by means of a non-spontaneous redox reaction, where an electric current is passed. It is carried out in a container called an electrolytic tank. Electrolysis is one of the main chemical separation methods. The main advantage of the electrolytic method is that it is not necessary to increase the temperature for the reaction to take place, thus avoiding energy losses and secondary reactions. Industrially, it is one of the most widely used processes in different areas, such as obtaining elements from compounds (chlorine, hydrogen, oxygen), metal purification (the metallic mineral is dissolved in acid, obtaining the pure metal by electrolysis) or the production of protective and/or decorative metal coatings, as in the case of nickel plating.
The following is the definition of some terms used in the electrodeposition process:
- Electrodeposit is the cathodic deposit obtained by the passage of an electric current in an electrolytic cell.
- An electrode is the component of an electrical circuit that connects the circuit wiring to a conductive medium such as an electrolyte. The positive electrode is called the anode and the negative electrode is called the cathode.
- The electrolyte is the ionic substance that in solution is decomposed by the passage of electric current.
Source: FES-CUAUTITLÁN Mtro. FELIPE DÍAZ DEL CASTILLO R.