Metal finishing requires precision and patience, especially when working with electroplating. The biggest challenge you face with metals is the threat of rust and corrosion, emphasizing the importance of a practical electroplating finish.
In its simplest terms, electroplating is the process of applying a metal finish onto an object through the use of electrical currents. The electroplating process is highly technical and requires quite a bit of equipment and expertise to apply a metal finish that lasts properly.
There is a long list of industries that use electroplating to improve the durability and conductivity of products. Whether you’re an engineer looking for a technical spec, changing your career, or simply just an interested party, this is your ultimate guide to electroplating.
Electroplating Process Explained
To get started with the electroplating process, you need four things: an anode, cathode, a DC power source, and an electrolytic solution.
1. Anode
The anode is the positively charged electrode or the metal material that will form the plating finish over the base metal.
2. Cathode
The cathode is the negatively charged electrode or the substrate. This is the base metal or the part that will be plated with a thin metal layered finish.
3. Electrolytic Solution
The electrolytic solution is where the entire electroplating reaction occurs. The solution is made with metal salts to create a flow of electricity to transfer the metals and apply a finish.
4. DC Power Source
The DC power source is the electrical charge needed to make a current powerful enough to create a reaction between the anode and cathode.
The Process
The anode is connected to the positive terminal of the power supply. The cathode is hooked up to the negative terminal. Once the connection is created, both the anode and cathode are fully immersed into the electrolyte solution. But before the complete electroplating process can continue, an electrical current must be established.
The DC power supply provides this electrical current, and once turned on, the anode receives power and begins to oxidize. Oxidation is when the metal atoms dissolve directly into the solution as the positive ions that were established.
The metal substrate is negatively charged and causes these positive ions to move towards the cathode (substrate) to form the thin metal layered finish. When the process remains constant, the anode can properly dissolve in the solution to apply a smooth and consistent finish onto the base metal.
Other Factors To Consider
Because of the many moving parts involved in electroplating, variables must be considered to apply a high-quality finish. If a finish is done below expectations, there is a strong chance one of these three factors was not correctly configured.
Bath Conditions
The bath is where the anode and cathode meet inside the solution. If the bath temperature or chemical makeup is off, the electroplating process will follow.
A misalignment in temperature will not allow the finish to stick onto the base material properly. The same goes for the chemical composition. Both factors are essential to the electrolytic solution and the quality of electroplating.
Placement Of Parts
The way parts are placed in the solution impacts the quality of the finish too. When the metals need to travel a farther distance, the finish applied to the substrate is of lower quality, and the anode struggles to stick onto the base material effectively.
Electrical Current
The electrical current is determined by the voltage level and the time parts are left in the solution. The effectiveness of the electroplating process relies on a properly timed application at the correct voltage levels to avoid burning and damaging the base material.
Electroplating Techniques
Electroplating can be executed in a few different ways. Each method creates a unique finish that best suits specific types of parts and metals.
Barrel Plating
Barrel plating is a way to plate large quantities of smaller parts by filling a barrel with parts and dipping it into the electrolytic solution. The barrel remains inside the solution and is rotated accordingly to shift the parts inside the barrel to create a more constant, even finish.
Barrel plating is highly effective on small parts due to its efficiency and flexibility for plating. It works best with finishes like gold, silver, palladium, rhodium, tin, copper, or nickel.
Electroless Plating
Electroless plating uses a similar application process but instead, there is no direct connection with electricity. The plating metal deposits onto the base material using a chemical reaction, eliminating the need for an electrical one that occurs in a traditional electroplated process.
Electroless plating is best used on parts with base materials that are not compatible with electrical currents. The process uses non-conductive substrates and reduces the number of metal atoms to apply the finish. Electroless plating is also referred to as conversion coating too.
Rack Plating
Rack plating is a popular option for a large number of parts. It requires the parts to be placed on a wire rack to allow each part to make a physical connection with the electrical power source to apply the metal finish.
Rack plating can be inconvenient and more expensive. It also presents risks to parts that are more sensitive to electricity or have an uneven shape that is difficult to properly place on a wire rack. The barrel plating method is an easier setup and better protects your parts from damages of direct electrical contact.
Electroplating Services Available
The electroplating process combines an individual metal with an alloy to add key characteristics to the finish. Some of the most effective metals for electroplating include:
Brass
Brass is a copper-zinc alloy made from a cyano-alkaline bath. Developing the bath is more difficult than a single alloy bath and consists of 70% copper and 30% zinc to create the brass finish.
Brass is also highly durable and does not rust. There are corrosion risks, but when coated with a clear protective coating like lacquer, you get a corrosion-resistant finish that creates an antique look after tarnishing.
Copper
Copper is known to be highly conductive with extreme heat and corrosion-resistant properties. It is a popular finishing choice for those looking to increase the adhesion capabilities of a part between multiple layers of material.
Copper is a highly active metal that may require a cyanide solution to ensure the appropriate adhesiveness levels are correctly reached. The copper finish is also dull but can be brightened with other additives.
Gold
Gold is a precious metal used to create a thin layered finish properly. Gold can prevent corrosion, increase electrical conductivity, improve wear resistance, and provide resistance to extreme heat levels.
Gold is also loved by many industries because of its aesthetic finish.
Nickel
Nickel plating can be applied as sulfate or sulfamate finishes through electrodeposition. Nickel is one of the most popular metals used, providing wear resistance, hardness, corrosion resistance, and conductivity.
Nickel is more versatile too. It is a low friction finish and comes at a fraction of the cost compared to other coating processes.
Tin
Tin is a matte metal with high corrosion-resistant properties. It is a more natural, environmentally friendly finish and highly non-toxic. This is why it is regarded by the food industry as a preferred finish.
Tin is inexpensive and highly solderable, providing excellent support to other industries like electronics and solar power too.
Silver
Silver is another precision metal but does not provide as much corrosion resistance as gold. However, it is very ductile and malleable and serves as a reliable gold alternative because of the high melting point and durability in low-oxygen environments.
The silver finish also provides a similar aesthetic feel as gold and is exceptionally lightweight and conductive.
Zinc
Zinc is a versatile finish with excellent strength, formability, and corrosion resistance. Zinc is a popular option to allow with other metals to increase the effectiveness of its properties. A combination of nickel and zinc creates a finish that withstands atmospheric corrosion well.
What Are The Benefits Of Electroplating?
Due to the variety of applications for electroplating, there are plenty of benefits to consider when deciding on the best metal finishing process for you.
1. Increases Aesthetic Appeal
The available metal finishes can enhance the exterior aesthetic appeal of your products. Using a finish like silver or gold not only provides added strength but gives your pieces a refined look without spending top dollar. Electroplating is used to prevent tarnishing, too, so your improved aesthetic comes with better longevity that improves over time.
2. Forms a Barrier
The electroplating process creates a protective barrier over the substrate to eliminate risks of damage to your initial base material. It works well against environmental conditions, corrosion, high temperatures, and more. The objective of an electroplated finish is to create a part that can withstand harsh conditions with ease.
3. Improves Heat Resistance
Many metals used in electroplating are designed to handle high temperatures. This allows the substrate to last longer because of the protective finish. Some of the most popular metals that provide excellent heat resistance include gold, silver, and zinc-nickel.
4. Reduced Friction
Because of the wide range of metals available for finishing, many benefits apply to each metal type. For example, nickel plating is the preferred choice for those looking to reduce friction on their parts to reduce part wear and increase longevity.
5. Increased Hardness
Surfaces that have been plated are less likely to be damaged if debris or the like falls on them. Nickel and palladium are two metals that provide excellent increases in hardness and quality of finish.
6. Adhesion Promotion
Copper plating is popularly used as a way to improve the adhesion abilities of a substrate that will have additional coatings applied. It ensures the finished product will be completely smooth.
7. Tarnish Prevention
Silverware tends to be plated to reduce the likelihood of it depreciating in both value and aesthetic appeal. Alongside this, scratches and other wear-and-tear dings will be prevented.
What’s The Best Electroplating Finish For Me?
If you are unsure what finish best suits you, give us a call to discuss the scope of your project, and a plating expert can assist you. Determining the best option is extremely important for you and your company, and electroplating is a perfect option to improve your products.
However, the initial decision process can be overwhelming. DiFruscia Industries, Inc. can help point you in the right direction and provide you all of the information needed to make your decision today.
DiFruscia Industries, Inc. Electroplating Services
DiFruscia Industries, Inc. has been serving the electroplating industry for over 60 years with the continuous development of new chemical and electrical metal finishing solutions. We can help you find the right finish and provide you with the best metal finishing service in the industry.
Contact DiFruscia Industries, Inc to get more information about the electroplating process and how exactly it can benefit both you and your business. Request a FREE quote today!
