Electroless plating is a manufacturing and finishing technique that is used to coat an object in a thin layer of metal. It is different from other plating techniques because it does not use an electrical charge to trigger a reaction. The process is completely chemical and is based on the concepts of reduction and autocatalytic reactions. Electroless plating is also known as autocatalytic plating for this reason. Many industries use this method of applying metal because the coatings are very hard, durable and resistant to corrosion. The technique also allows the plating of non-metallic materials like plastic.
The reason that electroless plating does not require an electrical charge is because the particles of metal that form the plating react directly with the surface of the object being plated. This means that every object must go through surface preparation before plating. The most basic type of surface preparation that is done on metallic objects involves a thorough cleaning in a number of different chemicals. Any type of debris, oil or residue on the surface of the object could create a very inconsistent or weak coating. Some metals must be activated by using acids. Any non-metallic object like plastic needs to have a special chemical pretreatment applied to the surface that will react to the metals used for plating.
The Electroless Plating Process
Electroless plating takes place in a large fluid bath that contains particles of the metal that will form the coating as well as a reducing agent. The items that will be plated is pretreated with chemicals and then lowered into the bath. The metal particles, reducing agent and the surface of the item all start an autocatalytic reaction. Electrons are swapped between ions. The eventual result is the attraction of the metal particles to the surface of the item where they form a permanent bond. Every part of the autocatalytic process must be carefully controlled. One of the most important factors is the homogenous distribution of the plating particles and the reducing agents in the bath. This is achieved by constantly agitating the bath.
Different types of plating and chemical combinations could require some processing after the coating is applied. An anti-oxidizer or other chemical might be applied to ensure the reaction stops. Cleaning chemicals could be used to prevent discoloration and staining on the surface of the item. Certain processes require baking in order to harden the surface for industrial use. Some proprietary coatings require only air-drying.
Items can be covered in a range of materials through electroless plating including nickel, palladium and copper. Electroless plating is a popular option for items that will be damaged or otherwise harmed by the electricity and chemicals that are used in electrostatic plating processes. The high resistance to corrosion and the durability of the plated parts have made electroless plating very common in oil drilling rigs, in components for marine equipment and in other applications where the part will be exposed to fluids. The lack of electricity has made electroless plating very useful for coating printed circuit boards and other delicate electronic elements.
This post was written by Karl Jonhson, a business owner in Toronto. He used the services of Cooper Plating when is company was developping a project that required electroless nickel plating. Their offices are at 1150 Nicholson Road Newmarket, ON L3Y 9C4 ?(905) 830-4007.