Metal spraying is a collective term for the various thermal spraying technology. Thermal spraying is based on the interaction between kinetic and thermal energy.
Metal spraying was developed in the early 20th century and originally included spraying of molten metal particles. Thermal spraying made it possible to apply materials on correctly prepared elements, without reaching the heat input necessary with welding or fusion.
The high kinetic energy generated in the metal spraying method led to mechanical clamping of the fusioned particles on a part without generating heat. Based on these findings thermal spraying was increasingly applied, initially mainly in repair. With the possibilities of using various devices in flame spraying, coatings in metal spraying can be provided - targeted to requirements and application area - in molybdenum, steel, stainless steel, and NE metals such as copper, bronze, aluminium, zinc (spray zinc plating) etc. as well as oxide ceramics.
To prepare the parts for metal spraying, they are degreased, heated at approx. 100°C, sprayed with steel shot, silica carbide or aluminium oxide and coated immediately afterwards to prevent corrosion. Should thermal spraying not be possible for the coatings, the treatment can be carried out by dry turning or dry grinding in specific cases.
The final processing of the coatings in metal spraying can be done by rotation, round grinding and finishing. In thermal spraying the coating is often also done without further treatment. Surfaces treated with metal spraying should then be lubricated or sealed depending on the use.
The various thermal spraying technology are further developed and because of new findings they have become a fixed element in wear and corrosion protection. Today, the terms of metal spraying methods such as wire flame spraying, beam flame spraying, powder flame spraying with or without self fluxing, high speed flame spraying (HVOF) are standardised under thermal spraying DIN EN 657.
Metal spraying covers applications for repair and to safe rejects due to defects to high technology with the indicated methods. The possibilities of thermal spraying are nowhere nearly exhausted yet and are always there for resolving technical problems. Thermal spraying is today a part of modern technology.