The coating technique of thermal spraying has developed into a technology with broad industry acceptance due to its varied capabilities. In light of increasing demands on construction materials, thermal spraying has become much more important over the last ten years. Requirements of both materials and components, like high corrosion or wear resistance as well as excellent mechanical properties, are often not present in components made from one single material. A use of materials which meets these requirements and solves this issue is achieved by distinguishing between the functions of the surface and structural core. Coating of highly stressed components by means of thermal spraying provides protection against wear, corrosion and also provides electric isolation or conductivity and heat insulation. Thermal spraying can also restore functionality of components after damage or replacement.
Thermal spraying materials are used in powder or wire form with a source of heat or first melted and then sprayed onto the component to be coated in the form of single spray particles. The material then cools and forms a spray coating. Before coating, the surface is cleaned and then roughened using rays.
Thermally sprayed coatings differ from those created using other processes in terms of structure, binding mechanics, and post processing options. Depending on the materials used and the method of spraying, coatings can vary in how porous they are. Manufactured coatings range between 40 μm and a few millimetres. The grip of sprayed coatings is based on mechanical grouting and also diffusion procedures which can have a bond strength of more than 100 MPa. The thermal load of the components during the coating depends on the process parameters. Through use of cooling attachments, it is possible to have substrate temperatures lower than 100 °C. A reworking of thermal coating using a stretching production technique is often necessary to ensure the required dimensional accuracy and desired finish quality.