Oxygen and fuel (acetylene most common) is fed into the barrel along with a charge of powder. A spark is used to ignite the gas mixture and the resulting detonation heats and accelerates the powder to supersonic velocity down the barrel. A pulse of nitrogen is used to purge the barrel after each detonation. This process is repeated many times a second. The high kinetic energy of the hot powder particles on impact with the substrate results in build up of a very dense and strong coating.
Characteristics of Detonation Spray Coating:
Material Form
Powder
Heat Source
Charge Detonation
Flame Temperature (°C)
3000 to 4000
Gas Velocity (m/sec)
> 1500
Porosity (%)
< 1
Coating Adhesion (MPa)
> 70
Advantages:
Excellent bond strength
Very dense coatings
Porosity less than 1%
Better coating characteristics of hardness,wear & corrosion resistance
Versatile process, ensuring wide range of coatings
Low process temperature enables spraying of precision components
