Phosphating, Powder coating and Metallizing MCQ with Answers

Electroless plating is a process of depositing a metal coating onto a substrate without the use of an external electrical power source. Unlike electroplating, which requires an electric current to drive the deposition of metal ions onto a substrate, electroless plating relies on chemical reactions to achieve the coating.

Decorative coatings produced through electroless plating are commonly used in various industries, such as automotive, electronics, and jewelry. The process is particularly useful for coating complex shapes and surfaces, including those with intricate details, where traditional electroplating might be challenging.

Several metals are commonly deposited using electroless plating for various applications. The choice of metal depends on the desired properties of the coating and the specific requirements of the application. Here are some popular metals deposited through electroless plating:

Nickel (Ni): Nickel is one of the most widely used metals in electroless plating. It provides excellent corrosion resistance, wear resistance, and hardness. Nickel-plated surfaces are often used for engineering applications, such as in the automotive and aerospace industries.

Gold (Au): Gold is known for its excellent electrical conductivity, corrosion resistance, and aesthetic appeal. Gold-plated surfaces are commonly used in electronics, connectors, jewelry, and decorative applications.

Silver (Ag): Silver is valued for its high electrical conductivity, making it a popular choice for electroless plating in electronics, electrical connectors, and some decorative applications. Silver also has antimicrobial properties, which can be advantageous in certain settings.

Copper (Cu): Copper is often used in electroless plating for its electrical conductivity. Copper-plated surfaces find applications in the electronics industry, where conductivity is crucial. However, pure copper is not commonly deposited via electroless plating due to challenges in achieving uniform coatings.

Electroless plating is chosen for particular metals or alloys based on the desired properties of the coating, the nature of the substrate, and the specific application requirements. The process involves chemical reactions that lead to the deposition of a metal layer on a substrate without the need for an external electrical power source. 

Electroless Nickel Plating (ENP) is the deposit of a nickel-alloy coating by chemical reduction – without the electric current that's used in electroplating processes. Acid type of solution is used for electorless nickel plating.