Metallizing consists of spraying particles of molten metal or alloy onto a roughened surface. The spraying takes place from a gun that melts the metal wire or powder fed into it. The molten metal is atomized with compressed air or inert gas and sprayed at high velocity onto the surface to be coated.
Metal Surgery uses two metallizing processes:
- Arc Spray
This process consists of the simultaneous advancement of two consumable wire electrodes that intersect at a point in an atomizing gas stream. An electric arc continuously melts the wire tips which are atomized into molten droplets which are deposited on the substrate to be coated.
- Thermal Spray by Wire or Powder
Wire or powder is melted by a gas flame and atomized with compressed air which propels the metal droplets onto the substrate to be coated.
Comparison of methods and comments.
- Arc spray is limited to the availability of alloy wire.
- Thermal spray by wire is limited to materials that are ductile and can be drawn.
- Thermal spray by powder can be used for coating ceramic materials.
- It is difficult to metal spray very thin layers. A thick layer must be sprayed and then machined.
- Metallizing is used for the repair of worn areas or to extend, restore or upgrade the life of a component.