Thermal spraying has developed into one of the most important coating processes. The main variants of the process are as follows:
- Flame spraying with powder or wire
- Atmospheric plasma spraying, plasma spraying in a vacuum or a controlled atmosphere
- High velocity flame spraying with powder or wire.
- Gas dynamic cold spraying of copper, steel, nickel or other metals and alloys with sufficient ductility
The range of gases required is as diverse as the surface coatings offered by these thermal spraying processes.
While flame spraying allows acetylene and pressures up to 2.5 bars to be used, much higher pressures between 5 and 8 bars are preferred for high velocity flame spraying. However, the trend is continuing towards higher pressures, up to 10 bars and more. High velocity flame spraying is used to produce high quality coatings with a high density as well as good adhesion and wear resistance. In order to guarantee these properties, it is necessary to work with high pressures.