Thermal Spraying is a deposition process during which molten particles caused by thermal sources such as plasma, arc or flame, impact at high velocity and solidify onto a substrate or previously deposited layers to form a thin coating.

With the development of science and technology, more and more materials and equipments with higher performance are required. However, investigations of these novel materials and their processes are usually complicated, cost- and time-consuming. Therefore, the material surface engineering has attracted much attention owning to its outstanding merits. As one of the important material surface technologies£¬thermal spraying is quickly developed because of its easy operation and lower cost, and has accounted for almost one third of the total surface engineering methods up to now. Thermal spray coatings are applied for some special functions such as corrosion resistance, wear resistance, high temperature resistance, oxidization resistance, insulation, heat insulation, electric conduction and radiation protection etc.