Electroless plating is a new type of metal surface treatment technology that uses a suitable reducing agent to reduce metal ions in the plating solution and deposit them on the surface of the substrate. Unlike electroplating, the electroless plating process does not require a rectified power supply and anode. It can be performed directly on metals, semiconductors and non-conductor materials, and has the characteristics of simple process, energy saving and environmental protection. Depending on the type of coating, electroless plating can obtain different functionalities, such as brazability, hardness, wear resistance, magnetic properties and corrosion resistance.