This volume introduces the other materials used for electroless plating besides nickel.

(1) Electroless gold plating

Gold-boron alloy plating is used for tiny electrical components.

(2) Electroless silver plating

Since early times, this method has been used as a silver mirror reaction in various fields. Examples of this plating are conductive treatment for giving an electroforming mother die the electrical conduction property and a mirror finish performed on the inner surface of thermos bottles.

(3) Electroless chrome plating

This displacement plating from trivalent chromium is not designed for depositing a thick layer.

(4) Electroless cobalt alloy plating

This metal works as magnetic plating and is used for memory apparatus. This type of plating includes cobalt-iron-phosphorus alloy, cobalt-tungsten-phosphorus alloy, cobalt-nickel-manganese alloy and more. Electroless plating composed of only cobalt is also available and used for high-density memory apparatus.

(5) Electroless tin plating

This method has long been used as immersion tin. This is also classified as displacement plating and is not designed for forming a thick layer. It is used for preventing rust temporarily or improving lubrication and solderability.

(6) Electroless copper plating

There are two methods available. With the first method, a layer of up to 1 µm can be deposited under normal temperature. In the latter method, a layer of between 20 and 30 µm can be deposited in a high-temperature bath. The first method is used for through-hole plating on printed circuit boards or conductive treatment for general plastic plating. The latter is used for circuit formation of printed circuit boards, etc.

(7) Electroless palladium plating

This low cost material with excellent electrical properties is used for electrical contact points and connectors as an alternative of gold plating.

(8) Electroless solder plating

The metal is deposited over copper on electrical components and printed circuit boards by displacement plating.

* What is electroless plating
Electroless plating is a technique used to deposit a layer of metal plating without using electrical energy provided to the plating bath from outside.
The reaction can be generally classified as follows:
Electroless plating = Chemical plating = Displacement plating + Autocatalytic plating
Only a thin layer can be deposited by displacement plating where the plated metal (workpiece) is dissolved into plating solution and the metal in the solution is deposited on the workpiece surface in return. The electroless plating generally refers to an autocatalytic process where the metal is deposited only on the workpiece surfaces with catalytic actions. This method allows you to deposit a thick layer.