Each material has its own characteristics and defects in performance. If several different materials can be organically combined together, the advantages of each material can be integrated, and their shortcomings can be compensated accordingly, so as to form a composite material with better performance than each single material, and even become a special material with special performance. With the continuous development of society, people expect to obtain various new materials with special functions to meet the functions that can not be obtained by a single material. composite materials is one of the most worthwhile and possible ways, and has become a key branch of materials science in the world. composite plating is a plating method developed in recent decades, and the related composite plating theory has made rapid progress;

By electrochemical deposition, insoluble solid particles are uniformly mixed into the metal coating to form a special coating, which is called composite coating. Composite plating is also called mosaic plating, dispersion plating or dispersion plating. If it is compounded by electroless method, it is called chemical composite plating; The electroforming method is called composite electroforming. The mechanism of composite electroless plating is not perfect up to now, unlike electrochemical deposition composite plating, which has formed a complete theoretical system. At present, through different combinations, insoluble particles can be discontinuously embedded in the electrodeposition process with a certain metal as the matrix, such as Chromium-based composite electroplated ceramics . The insoluble solid particles used in this kind of composite layer are generally micron or even nano-scale powders. Different powder materials are selected according to the functional requirements, such as silicon carbide powder, boron nitride powder, molybdenum disulfide powder, ceramic powder, graphite powder, polytetrafluoroethylene powder, etc. This kind of composite coating can often play a wear-resistant and self-lubricating properties;

Compared with other methods such as metallurgical methods, chemical methods have many advantages, such as low operating temperature, easy control, diversity, etc. Moreover, only the surface properties of materials are modified, which can save costs.

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