** These are the most popular coatings for aggressive/abrasive environments
- Powders available including:
- **Tungsten carbide/cobalt/chrome (86-10-4) (Diatec 1086)
- **Nickel/chrome/boron alloy (Diatec 1060)
- (or Nickel/chrome/boron with tungsten carbide matrix)
- Chrome carbide
- Tungsten carbide (various blends)
- ** Inconel 625 and 718
- Hastelloy, stainless steel, nickel (and almost any commercially available metal)
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HVOF Spraying
Diatec 1086 (Wc, Co, Cr) - Is the most widely used HVOF coating; as well as having a greater hardness than chrome plating, it is also better in corrosive and erosive environments.
Diatec 1060 (Ni, Cr, B) - Is widely used as a replacement to chrome plating.
Diatec 1062 - Has been approved for reclamation of Inconel, super duplex shaft seal and bearing areas.
What is High Velocity Oxygen Fuel Spraying?
HVOF is a spraying process where a mixture of gaseous or liquid fuel and oxygen is fed into a combustion chamber, where they are ignited and combusted continuously.
The resultant hot gas emerges through a converging–diverging nozzle and then travels through a straight section.
The fuels can be gases (methane, propane, propylene, acetylene, hydrogen, or natural gas, etc.) or liquids such as kerosene, etc..
The jet velocity at the exit of the spray gun barrel is usually greater than 1000 M/s. this exceeds the speed of sound.
One of a large selection of powdered coating stocks is fired into the gas stream, which accelerates the powder up to approximatelt 800 M/s.
The stream of hot gas and powder is aimed towards the surface requiring the coating.
Due to the temperatures reached the powder partially melts in the sprayed stream, and hits the substrate where it bonds to the surface and then to itself building up a layer to a desired thickness.
The resulting coating has lower porosity and higher bond strength compared to most other methods.