What is Metal Plating: Processes, Types & Applications
Manufacturers opt for different types of metal plating to create a layer of protection on the custom components. Metal plating has various advantages and types. If you are interested in knowing what is metal plating and how it is applied, the guide below is for you.
What is Metal Plating?
Metal plating is composed of creating a layer of different metals like copper, chromium, or nickel on the components. It makes components resist corrosion and appear visually appealing. Metal plating has many benefits for the components that are made using versatile materials.
The surface roughness of the components improves, and also an aesthetic appeal is achieved, which helps in enhancing the hardness.
Working Steps for the Metal Plating Process
The process of metal plating has many steps, and the entire procedure is discussed below:
Step 1: Pretreatment
The process of pre-treatment helps in removing all the contaminants on the component that needs to be coated. The presence of these contaminants may lead to problems with the plating process. The pre-treatment uses the method of rinsing, cleaning, and other types of processes.
Step 2: Determine the Effectiveness of the Cleaning
The part's function and nature determine the process of plating, and similarly, the cleanliness of the component also determines what type of plating will be done. Some techniques of plating require the dirt and soil to be removed, but some may need oil and grease removal.
Step 3: Set up the Plating Station
The plating station setup requires setting up for the electroplating process. You will need all the essential tools and materials like a cathode, anode, a tank, and the required plating solution.
Step 4: Plating
The process of deposition starts the moment electric current passes. If you need thicker plating, you need to conduct the process for a longer span. For a thinner one, you need to expose it for a shorter time. However, parameters like voltage, temperature, and immersion time should be considered.
Step 5: Post-Treatment
Post treatment cleaning is essential for achieving the required deposition on the component. It may consist of considering electrolytic polishing, which improves and protects components from corroding.
Step 6: Waste Disposal
The process of plating metals produces heavy metals, which can be highly toxic. Hence, they should be disposed of carefully. Make sure to plan proper disposal of the materials for safety.
Types of Metal Plating
There are different types of metal plating that can be selected and these are discussed below.
1. Zinc Plating
Zinc is a very affordable material, and zinc plating is composed of dipping the component in zinc. The component takes the position of the cathode, and zinc takes the position of the anode. They are dipped in zinc salt electrolytic solution. Zinc plating creates a ductile coating on the component with uniform thickness.
2. Chrome Plating
Chrome plating involves using chromic acid, which improves the aesthetic finish of the components. Chromium plating improves the material hardness and enhances its corrosion resistance.
3. Nickel Plating
Nickel plating creates a layer of protection on products like fixtures of showers, door knobs and cutlery. It enhances the wear resistance as well as aesthetic appeal. It is suitable for copper and aluminium components.
4. Copper Plating
Copper is an affordable type of material when it comes to metal plating; it offers high electrical conductivity. It is opted for electronic components like circuit boards.
5. Cadmium Plating
Cadmium plating is a silver-coloured coating that is applied to the base of metals like steel, iron, copper, and aluminium. The process of cadmium plating is suitable for the components like screws and bolts used in submarines. It is highly corrosion-resistant, solderable, and malleable.
6. Silver Plating
Silver plating is similar to gold plating, and it enhances the visual appeal of the materials. It offers high electrical conductivity and is also used due to its affordability.
7. Gold Plating
Gold plating offers high electrical conductivity. It is a very effective method that transfers the properties of gold to silver and copper. It is mostly used in electronic components.
8. Tin Plating
Tin plating deposits a layer of tin on the surface of the material with the help of an electrical current. This plating is very cost-effective as tin is commonly available and is less expensive compared to other types of plating metals.
9. Rhodium Plating
Rhodium plating consists of depositing a thin layer of rhodium on the jewellery. It improves the durability, shine and reflectivity of the components.
10. Aluminum Plating
Aluminum plating refers to the method of coating a component with aluminum. Aluminum plating is opted for improving the corrosion resistance, wear resistance, and appearance of the component.
Common Metal Plating Techniques for Custom Parts
There are different methods for metal plating, which are given below.
Electroplating
It involves the deposition of a layer of one metal on another using electricity. It consists of using an electrolyte solution, which deposits the ions by attaching the workpiece.
Electroplating improves the chemical as well as physical properties of the component. It offers a very quick and easy way of coating a metal. A layer of thin coating creates aesthetic appeal as well as protection on the metal components.
Electroless (Autocatalytic) Plating
Electroless plating is a method that is opted as an alternative to electroplating. It doesn't use any type of electric current for plating. This process can deposit metals like silver, gold, copper, and nickel on the surface of the materials with the help of a chemical bath. It creates a catalytic reduction reaction and doesn't need any electricity for the process.
It is a suitable process for plating the components which have hard surfaces and need corrosion resistance. Components used in marine and oil and gas industries are mostly subjected to this method.
Immersion Plating
Immersion metal plating consists of immersing the metal in a chemical component that has metal ions. The ions are of a noble metal and they offer stability. A thin layer of these metal ions is deposited on the metal part, and it is coated. Most of these noble metals are platinum, gold, and silver.
Carburizing
Carburizing is a process of metal plating which solidifies on the surface of the metal. The process of carburizing is done after the component has been machined. It helps to prevent corrosion. It develops a thin metal layer on the components.
Physical Vapor Deposition (PVD)
PVD metal plating consists of creating a thin layer of metal on the surface. It sublimes the component and creates a layer of film for protection. It takes place in the presence of gas or low-pressure plasma. PVD coating makes the surface adhesive and offers excellent diffraction.
Plasma Spray Coating
Plasma spray coating is a very effective and flexible thermal spray method that uses melted material to spray on the components. It is compatible with various materials like metal and ceramics. It uses jet engine protection for restoring worn-out parts. It offers seamless abrasion, heat and wear resistance.
Benefits and Limitations of Metal Plating
Some of the benefits of metal plating are as follows:
- Metal plating improves the aesthetics of the component.
- Metal plating is versatile and can cover a wide range of materials.
- It makes components wear-resistant.
- Metal plating makes the component strong.
- It is an affordable method of finishing.
The downsides of the metal plating are as follows:
- Metal plating can crack in specific environments.
- It is a complex process and may impact the specification of components.
Applications of Metal Plating Finishes
Metal plating is used in many industries for versatile applications, and some of the industries using metal plating finish are as follows:
Aerospace: Aircraft components require metal plating to increase their life and reduce corrosion. This process adds a layer of metal, improving the components' functionality so that they can work in varying environments.
Automobile: The automobile sector uses electroplating for the custom components of vehicles, which is based on conceptualization. They use multiple types of electroplating methods including chromium, nickel, and other types of metals.
Medical: The medical industry uses metal plating for producing different instruments, medical and dental, like tooth inlays.
Jewelry: Jewelry is metal plated to improve the aesthetic look and durability of the different pieces like pendants, rings, and bracelets.
Factors to Consider for Metal Plating
When considering metal plating, some of the important factors to consider are the following:
Pre-plate Material Conditions
The condition of the material before plating requires analysis, it should be ready for plating and needs to be clean from all types of contaminants, grease, and residue. Make sure to remove the build-ups on the component using different techniques and prepare the material for metal plating.
Thickness Tolerance
The thickness of the coating is crucial when it comes to components that require specific tolerances. Hence, you must decide the maximum and minimum level of thickness a component may have, followed by the metal plating.
Thread Inclusion
The components that have threaded features require careful consideration when plating them. It is because compared to the flat surfaces, these features take a thickness of about four times. Hence, it is essential to consider their metal plating when manufacturing so that they can fit perfectly.
Conclusion
Metal plating is a common form of finish adopted by many manufacturers for the components. If you have an upcoming project where you need to have your components metal-plated, feel free to contact us at DEK. We have various processes for metal plating based on your application requirements and the component material to offer.
