Coating material in powder form is fed into a heat source created by ionization of a gas in an electric arc between two electrodes. The substrate and coating material is locally melted to form a metallurgically bonded coating. The coating has very low dilution compared to conventional welding.

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In powder flame spraying, the spraying consumables in powder form are melted in an acetylene-oxygen flame and are accelerated on to the prepared surface by means of expanding combustion. You distinguish the powder between self fluxing and self bonding spray powder. This melting process is mostly carried out with the suitable acetylene-oxygen torch.

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A mixture of gaseous or liquid fuel and oxygen is fed into a combustion chamber, where they are ignited and combusted continuously. The fuels can be gases (hydrogen, methane, propane, propylene, acetylene, natural gas, etc.) or liquids (kerosene, etc.). The jet velocity at the exit of the barrel (>1000 m/s) exceeds the speed of sound. A powder feed stock is injected into the gas stream, which accelerates the powder up to 800 m/s.

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In plasma spraying process, the material to be deposited typically as a powder, is introduced into the plasma jet. In the jet, where the temperature is in the order of 10,000 K, the material is melted and propelled towards a substrate. There, the molten droplets flatten, rapidly solidify and form a deposit. Commonly, the deposits remain adherent to the substrate as coatings;

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