Have you ever reclined back and marveled at a painting in your house with a gilded frame and wondered, ‘Just how did they do that?’ Have you ever wondered how the electroplating process works?
Well, you’re in the right place, for this is exactly what we are going to be investigating today!
Table of Contents
- What is Electroplating?
- Electroplating Jargon
- Metals Used in Electroplating
- How Electroplating Works
- Different types of Electroplating
- What’s So Great About Electroplating Anyway?
- Final Words
- FAQs Electroplating
What is Electroplating?
Otherwise known as electrochemical deposition or electrodeposition, Electroplating is a process for producing a metal coating on a solid substrate through the reduction of cations of that metal by means of a direct electric current.
The item to be coated acts as the cathode (negative electrode) of an electrolytic cell, if, of course, we are to take the electrolyte as a solution of a salt of the metal to be coated, and the anode (positive electrode) to be either a block of that metal or of some other inert conductive material. The current is then provided by an external power supply.
Electroplating has found many uses in industry and decorative arts to improve the surface qualities of objects – i.e. resistance to abrasion and corrosion, lubricity, reflectivity, electrical conductivity, and/or appearance.
It can be used to build up thickness on undersized or worn-out parts or to manufacture metal plates with complex shapes, an extension of the process referred to as electroforming. It can also be used to deposit copper and other conductors in forming printed circuit boards, and copper interconnects in integrated circuits, as well as to purify metals such as copper.
Electropolishing, a process that uses an electric current to remove metal cations from the surface of a metal object, is the reverse of the process of electroplating, though both processes will no doubt be fascinating to anyone who seeks to learn about electroplating for the sake of gilding.
How does it actually work, though? How does this process look in reality? It’s all well and good listing a whole bunch of terms and conditions, but what is the actual process like? Can you do it at home? No? If so, why not?
Electroplating Jargon
Before proceeding, it might be best to clear up any confusion regarding the specific terminology used in electroplating, whether that be gold plating, copper plating, nickel plating, or silver plating.
- Anode: positively charged electrode, the metal that will form the plating.
- Cathode: the part that needs to be plated. also called the substrate. This part acts as the negatively charged electrode in the circuit.
- Solution: The electrodepositing reaction takes place in an electrolytic solution. This solution contains one or more metal salts, usually including copper sulfate, to facilitate the flow of electricity.
- Power source: Current is added to the circuit using a power source. This power source applies a current to the anode, introducing electricity to the system.
Metals Used in Electroplating
If the process of electroplating can involve so many different metals in various combinations, what are these metals?
- Copper: used for its conductivity and heat resistance. It is also commonly used to improve adhesion between layers of material.
- Zinc: highly corrosion-resistant and often alloyed with other metals to enhance this property. For example, when alloyed with nickel, zinc is particularly resistant to atmospheric corrosion.
- Tin: This matte, bright metal is highly solderable and corrosion resistant as well as environmentally friendly, not to mention being relatively inexpensive compared to other metals.
- Nickel: offers excellent wear resistance which can be improved further through heat treatment. Its alloys are also very valuable, offering elemental resistance, hardness, and conductivity. Electroless nickel plating is also valued for its corrosion resistance, magnetism, low friction, and hardness.
- Gold: offers high corrosion, tarnish, and wear resistance and is coveted for its conductivity and aesthetic appeal.
- Silver: not as corrosion resistant as gold but still highly ductile and malleable, with excellent resistance to contact wear and excellent aesthetics. It is also an apt alternative to gold in applications where thermal and electrical conductivity is needed.
- Palladium: often used instead of gold or platinum for its hardness, corrosion resistance, and beautiful finish, when alloyed with nickel, this metal achieves excellent hardness and plating quality.
How Electroplating Works
To begin, determine which anode, cathode, and electrolyte to use by determining which chemical reaction or reactions you want to occur when the electric current is turned on.
The next step is to make sure that the electrodes you’re going to plate are entirely clean. If not, when metal atoms from the electrolyte are deposited on it, they will not establish a strong bond and will rub off.
Cleaning is usually accomplished by putting the electrodes in an acid solution or acidic mixture or (briefly) reversing the electroplating circuit. If the electrode is exceptionally clean, atoms from the plating metal form a strong link with it by adhering to the crystallographic craft’s exterior borders.
A positive ion is an atom with too few electrons. When such a thing reaches the cathode, it combines with electrons and loses its positive charge. A negatively charged ion, then, is an atom with too many electrons. When this reaches the positive anode, it transfers electrons to the anode and loses its negative charge.
In some forms of electroplating, the metal to be plated is at the anode of the circuit and the material to be plated is at the cathode. After a period of reaction, the positively charged metal molecules will slowly migrate to the negatively charged metal surface, forming a very thin layer, which is called the coating.
Different types of Electroplating
As previously alluded to, perhaps it would be best now to explore some of the different types of electroplating, even if they all function in the same processes.
Barrel Plating
A method used to plate large groups of small parts. Here, parts are placed inside a barrel filled with an electrolyte solution, the electroplating process proceeding while the barrel is rotated, agitating the parts so that they receive consistently even finishes. Barrel plating is best used on small, durable parts, but offers a cheap, efficient, and flexible solution to the electroplating problem.
Rack Electroplating
Otherwise known as wiring plating, this is a good option if you need to plate large groups of parts. Here, parts are placed on a wire rack, allowing each part to come into physical contact with the electrical power source. Albeit more expensive, this option is optimal for more delicate parts that cannot undergo barrel plating. It is, however, important to note that rack plating is more difficult for parts that are sensitive to electricity or have an irregular shape.
Electroless Plating
Otherwise known as autocatalytic plating, this version uses a similar process as electrodeposition but does not directly apply electricity to the part. Instead, the plating metal is dissolved and deposited using a chemical reaction in place of an electrical one. While this option is useful for parts that are incompatible with electrical currents, it is more costly and less productive than other options.
What’s So Great About Electroplating Anyway?
Seeing as it takes so much effort, you might wonder why people bother in the first place. Well, wonder no longer!
Protective Barrier
Electroplating creates a barrier on the substrate, protecting it against adverse environmental conditions. In some cases, this barrier can protect against corrosion caused by the atmosphere too. This corrosion protection benefits components because the parts last longer in harsher conditions, meaning that they need less frequent replacement.
Enhanced Appearance
Exterior pieces are often plated with thin layers of precious metals to make them more lustrous and attractive to look at. This plating lends aesthetic appeal without exorbitant costs, meaning that attractive parts can be sold at lower prices. Additionally, electroplating is often used to prevent tarnishing on silverware, improving longevity as well as aesthetic appearance over time.
Electrical Conductivity
Silver and copper plating help improve electrical conductivity in parts, offering a cost-effective, efficient solution for improving conductivity in electronics and electrical components.
Heat Resistance
Several metals, including gold and zinc-nickel, are resistant to high temperatures, improving the ability of the substrate to resist heat damage. This, in turn, can improve the lifespan of plated parts.
Improved Hardness
Electroplating is often used to improve the strength and durability of substrate materials, making them less susceptible to damage from stress or rough use. This quality can help increase the lifespan of plated parts, reducing the need for replacement.
All of this seems to suggest that electroplating is largely for the longevity and luster of physical objects, and you would be right, especially on this website, where gold leaf is our number one priority.
Final Words
So, there you have it! Hopefully, you are now feeling ready and able to educate the masses on your newfound love of electroplating!
FAQs Electroplating
The electroplating process is a process by which to plate an object for reasons pertaining to strength, protection, and luster.
Electroplating is a process by which people plate objects – for the purposes of protecting objects from corrosion and decay, as well as to improve their overall luster.
Perhaps if you already have all of the equipment necessary to charge the metals involved in the process. If you don’t, though, then this might be a far more difficult process.
Electroplating is a specific process under the umbrella of metal plating (of which there are various other varieties, including electroless plating).
The anode and cathode are placed in an electrolyte chemical bath and exposed to a continuous electrical charge. Electricity causes negatively charged ions to move to the anode and positively charged ions to transfer to the cathode, covering or plating the desired part in an even metal coating.
It is a broadly effective and relatively inexpensive way to protect objects from corrosion while providing them with a renewed luster, though thus all depends on the objects you’re plating and the specific electroplating process you are using.
The thickness of electroplating is various, though it typically ranges from 0.0001 inch to 0.020 inch (0.0025 mm 0.508 mm).
