In a plasma sprayer, an arc gas is ionized between an anode and a cathode. The plasma that is created can reach a temperature of up to 15,000°C. The powder injected into the plasma jet is melted and deposited on a substrate.
The high heat level and conductivity of the plasma flame, in combination with the very high gas- and transport velocity of the molten particles result in optimal condtions for very strong adhesion, uniformity and purity of the sprayed layer.
Because of the high temperatures there are hardly any restrictions to the materials that can be sprayed. However, plasma spraying is extremely suitable for spraying materials with a high melting point such as oxides. An important application is the application of thermal barrier coatings (TBCs).
If there is a risk of chemical fluids or hydraulic oil penetrating the pores of the layer and thus reaching the base material, the flame sprayed layers can be hermetically closed with a sealer.
Features of plasma spraying:
- Fine microstructure
- Low porosity
- Good resistance to corrosion
- High process flexibility
- Good tensile strength
- Versatile and high choice of materials
- High production capacity
Plasma spray materials
Many spray materials are used for plasma spraying:
- C- and stainless steel
- Special alloys
- Exothermic materials
- Chromium and tungsten carbides
- Ceramic materials
- Oxides and mixtures
- High melting point metals
- Ceramic materials (oxides)
- Cermets, carbides
- Metals and metal alloys
- Virtually all materials to be sprayed
Applications of plasma spraying
Ceramic sealing surfaces
Against running into the seals.
Hydraulic piston rods
In the offshore to protect the seawater environment.
Repairs or size corrections
From run-in journal or bearing seats.
With Molybdenum for wear resistance and better running properties and a lower coefficient of friction.
Thermal barrier coatings
In gas turbines.
Metalo is supplier for a.o.
Flame spray is a unique and practical technique to apply a coating to almost any kind of metal and non-metal surfaces. This coating improves the basic material properties such as hardness, abrasion, scratch and corrosion resistance.
HVOF flamespray forms a coating with a high density and a high bonding value. The HVOF flamespray principle is based on a transfer of thermal and, in particular, kinetic energy from the spray particles of the substrate.
Electric wire spraying is a form of thermal spraying where two consumable metal wires are fed independently into the spray gun. With electrical wire spraying, coatings can be applied quickly and at low cost.
For corrosion protection, repairs or size corrections. The spray layers applied in this way are more or less impact or shock resistant. The structure of the layer is always micro-porous. This gives the ability to hold oil and thus self-lubricating properties are obtained.