Do you want to electroplate your metal parts? If so, you need to know about electroplating finishes. Many different types of electroplating finishes are available, and each has its own benefits and drawbacks. This blog post will discuss the different types of electroplating finishes and help you decide which one is right for your needs. We will also talk about the process of electroplating and help you understand how it works.
What is electroplating?
Electroplating is applying a thin layer of metal to another object. This can be done for many reasons, including protecting the object from corrosion, increasing its electrical conductivity, or giving it a different appearance.
There are two types of electroplating: direct electroplating and indirect electroplating. Direct electroplating is when the metal ions are directly deposited onto the object to be plated. Indirect electroplating is when the metal ions are first deposited onto an electrode, and then the electrode is placed in contact with the object to be plated.
How does electroplating works?
Electroplating works by using an electric current to deposit a thin metal layer onto an object. The object to be electroplated is placed in an electrolyte solution, and a negative charge is applied to it. This attracts positive ions from the solution to the surface of the object, where they form a thin layer of metal.
Electroplating is often used to give objects a different appearance. For example, electroplating can give metal objects a gold or silver finish. It can also be used to add color to an object by adding a thin layer of another metal.
The beauty of electroplated objects after electroplating is related to the size of the current; the smaller the current, the more beautiful the objects will be electroplated; Otherwise, there will be some uneven shapes.
The Steps of Metal Parts Electroplating
There are four main steps in the plating process:
① Polishing: The electroplated object is polished to remove imperfections and give it a smooth, shiny finish.
② Cleaning: The object to be electroplated must be clean and free of dirt, grease, and other contaminants. This step is important because it ensures that the plating processes will be successful.
③ Electroplating: The object is placed in an electrolyte solution, and a negative charge is applied to it. This attracts positive ions from the solution to the surface of the object, where they form a thin layer of metal.
④ Finishing: The electroplated object is removed from the electrolyte solution and allowed to dry.
Electroplating Process
Anode: The anode, or positively charged electrode, is the metal that forms the coating in a circuit.
Cathode: The cathode in an electroplating circuit is the part that needs to be electroplated. It’s also called a matrix. This part acts as a negatively charged electrode in the circuit.
Electrolyte: It is a liquid that helps to provide electrical conduction between the object being plated and the electrode. Without electrolytes, electroplating would not be possible!
Power source: In electroplating, the power source is an important part of the process. It provides the electricity that is needed to plate the metal object with a layer of metal.
What are the different types of electroplating finishes?
The technique of depositing a metal coating with good adhesion but different properties and substrate materials on a mechanical product using the electrolytic cell principle. Electroplating is more uniform than the hot dip layer, generally thinner, ranging from a few microns to dozens of microns. Electroplating provides a decorative protective and functional surface layer on mechanical products, and worn and faulty parts can be repaired.
The electroplating process can be used to plate many different metals, including copper, nickel, gold, and silver. Each metal has its own unique benefits and drawbacks.
Some common electroless plating finishes include:
Copper Plating
It is generally used as an intermediate layer of other coatings to improve the bonding between the surface coating and the base metal. In the electric power industry, thick copper electroplating can be used to replace all copper to reduce copper consumption.
Copper is easy to oxidize, oxidation copper is no longer conductive, so copper plating products must protect the copper.
Nickel Plating
The electroplating nickel layer in the atmosphere of consolidation is very high because the metal nickel has a very strong passivation talent; on the surface can quickly generate a very thin passivation film and can resist the atmosphere, alkali and some acid erosion.
The use of nickel p
lating surface is very wide and can be used as a protective decorative coating in steel; zinc dies casting, aluminum alloy, and copper alloy surfaces protect the substrate material from erosion or bright decorative benefits.
“Note that many electrical componets, such as DIN heads and N heads, no longer use nickel base, mainly because nickel is magnetic, which will affect the passive intermodulation in the electrical properties.”
Gold Plating
Electrogilding is the most important and commonly used gilding process. After the product to be gilded is energized, an electric current will be generated in the gilding liquid, and an electric field will be formed to release electrons, which will be combined with gold ions and finally deposited on the surface of the gilding product to form a gilding layer.
The main role of gold plating is as an object decoration, but also to the object to play the role of corrosion. The use of gold has good conductive properties, reduces resistance, and improves conductivity.
Sliver Plating
Silver electroplating. The coating prevents corrosion and increases conductivity, reflection and appearance. Widely used in electrical appliances, instruments, meters and lighting appliances and other manufacturing industries.
Palladium Plating
Palladium is a platinum group metal with a dull white colour. Palladium coating is mainly used in the electronics industry, accounting for more than 40% of the demand for palladium. The second type is used as a catalyst, mainly in the jewellery and dental industries.
The physical properties (hardness, flexibility, thermal stability) of palladium coatings are better than those of hard gold coatings, but the cost is much lower than that of hard gold. There are decorative plating palladium layers in the appearance of silver, which can also be used instead of rhodium plating.
Zinc Plating
Galvanized refers to the surface of the metal, alloy or other materials coated with a layer of zinc, play beautiful rust and other effects of surface treatment technology.
The key role of galvanized in steel parts is anti-corrosion; Galvanized has the advantages of low cost, good corrosion protection, beautiful storage and other advantages, widely used in light industry, mechanical and electrical, national defence and other fields;
Stannum Plating
Tin plating is widely used in food canned packaging products, drinks, kitchen utensils and the electronics industry in many parts that must be fibre welding.
Chrome Plating
Chromium can maintain lustre in the atmosphere for a long time, and is unreactive in lye, nitric acid, hydrochloric acid and many organic substances. Chromium plating has high strength, good wear resistance and low friction resistance.
Therefore, chromium plating is often used to maintain decorative coating, avoid base metal rust, beautify the appearance, improve the wear resistance of goods or repair damage.
The benefits of electroplating
A technique in which a metal coating with good adhesion but different properties and substrate materials are deposited on a mechanical product by electrolysis. Electroplating is more uniform than the hot dip layer, generally thinner, ranging from a few microns to dozens of microns. Electroplating provides a decorative protective and functional surface layer on mechanical products, and worn and faulty parts can be repaired.
Common benefits of electroplating include:
- Prevent corrosion: It can prevent the metal surface from corroding in harsh environments. Such as galvanized cadmium plating on the surface of steel workpieces.
- Improve durability: It can improve the durability of metal surfaces. Such as chromium plating on the die surface improves the die surface’s hardness and wear resistance.
- Improved solderability: It can improve the solderability of metal surfaces, such as electroless nickel plating, electroless palladium plating and other surface finish processes.
- Enhance appearance: It can enhance the appearance of the metal surface. Such as stainless steel jewellery surface gold and silver plating.
- Improve the conductivity: To improve the workpiece’s electrical conductivity, the general processing plant will plate copper on the surface of the workpiece.
- Repair part size： For example, shaft, gear and other important mechanical parts wear after use and can be used in iron plating, chromium plating and other disasters.
What are the metal plating methods?
Electroplating is divided into hanging plating, roll plating, continuous plating and brush plating, mainly related to the size and batch of parts to be plated.
- Hanging Plating
The workpiece’s surface is immersed in a plating solution, and the anode and cathode are connected to the power supply. When current is passed through, metal ions in the plating solution are reduced on the workpiece’s surface under an electric field’s action to form a dense and uniform electroplating layer.
Hanging is putting the parts one by one on the holder; the effect of hanging plating will be much better, but the unit price will be higher.
- Roll Plating
The workpiece’s surface is immersed in a plating solution, and the anode and cathode are connected to the power supply. When current is passed through, metal ions in the plating solution are reduced on the workpiece’s surface under an electric field’s action to form a dense and uniform electroplating layer.
Hanging is putting the parts one by one on the holder; the effect of hanging plating will be much better, but the unit price will be higher.
- Continuous Plating
Continuous electroplating is the process of electroplating a workpiece through an automated electroplating line. Continuous electroplating is also known as roll-to-roll electroplating, and the material is generally ribbon that can be rolled up, such as steel belts or continuous stamping products.
Each electroplating tank is generally divided into the mother tank and the child tank, the potions from the mother tank pump into the child tank, there are gaps on both sides of the child tank, the material to be plated through the gap, the potions into the child tank from the gap outflow into the mother tank, because of the inflow outflow speed difference, you can maintain a certain level.
- Brush Plating
Brush plating is also known as coating or slotless plating. Its principle and essence belong to the electroplating process in electrochemical processing. It is the opposite of electrolysis, the use of metal ions in the electro bath under the action of the electric field, plating deposition to the cathode up the processing process.
Brush coating thickness is generally less than 0.5mm, with no processing or a little processing after plating, so the parts to be plated surface before plating should be processed to meet the shape accuracy and surface roughness requirements in order to obtain uniform coating.
What are the electroplating colours?
The electroplated metal determines the electroplating colour.
For example,
chromium plating is silver white,
nickel plating is silver white or light yellow,
copper electroplating is golden yellow,
electroless nickel plating can be divided into bright and dull, two kinds of electroplating colours.
In addition, there is some special electroplating; the electroplating colour is also based on electroplated metal.
For example,
black nickel plating is actually electroless nickel plating, and then through the chemical or electrolytic method to add a layer of black nickel based on electroless nickel plating;
blue chromium plating is actually chromium plating and then electroplated with a layer of blue chromium based on chromium plating. Electroplating colour also has electroplated metal, such as electroless nickel plating black, then electrolytic copper and then electroless nickel plating black; or after anodizing, using electrolytic colouring method to form a variety of colours.
FAQs
Q: What are the electroplating colors?
A: The electroplating colour is determined by the electroplated metal. For example, chromium plating is silver white, nickel plating is silver white or light yellow, copper plating is golden yellow, and electroless nickel plating can be divided into bright and dull two kinds of electroplating colours.
Q: What is the difference between electroplating and anodizing?
A: Electroplating is to use the electrochemical principle, make the workpiece on the surface of a layer of metal deposition; anodizing is to use the electrolysis principle, make the workpiece on the surface of a layer of the oxide film.
Q: Can non-metallic parts be electroplated？
A: No. In electroplating, the ions of the electroplated metal must be deposited on the surface of a conductive object, so that non-metallic parts cannot be electroplated.
Q: What are the benefits of electroplating?
A: Electroplating can increase the wear resistance, Improve corrosion resistance, mechanical properties, and electrical conductivity of the workpiece. It can also be used to build up worn surfaces, repair damaged surfaces, or change the appearance of the workpiece.
Q: What are the disadvantages of electroplating?
A: One disadvantage of electroplating is that it can introduce stresses into the workpiece. Another disadvantage is that electroplated coatings are often not as thick as mechanically deposited coatings, so they may not provide the same level of protection. Finally, electroplating can be a time-consuming process.
Author
Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.