Thermal spraying can provide thick coatings (approx. thickness range is 20 microns to several mm, depending on the process and feedstock), over a large area at high deposition rate.
Coating materials available for thermal spraying include metals, alloys, ceramics, plastics and composites.
They are fed in powder or wire form, heated to a molten or semi molten state and accelerated towards substrates in the form of micrometer-size particles. Combustion or electrical arc discharge is usually used as the source of energy for thermal spraying.
Coating quality is usually assessed by measuring its porosity, oxide content, macro and micro-hardness, bond strength and surface roughness. Generally, the coating quality increases with increasing particle velocities.
Several variations of thermal spraying are distinguished:
- Plasma spraying
- Detonation spraying
- Wire arc spraying
- Flame spraying
- High-velocity oxy-fuel coating spraying (HVOF)
- High-velocity air fuel (HVAF)
- Warm spraying
- Cold spraying
- Crankshaft reconditioning or conditioning
- Corrosion protection
- Fouling protection
- Altering thermal conductivity or electrical conductivity
- Wear control: either hardfacing (wear-resistant) or abradable coating
- Repairing damaged surfaces
- Temperature/oxidation protection (thermal barrier coatings)
- Medical implants
- Production of functionally graded materials (for any of the above applications)
Content from Wikipedia: https://en.wikipedia.org/wiki/Thermal_spraying