Detonation spraying is one of the many forms of thermal spraying techniques that are used to apply a protective coating at supersonic velocities to a material in order to change its surface characteristics. This is primarily to improve the durability of a component. It was first invented in 1955 by H.B. Sargent, R.M. Poorman and H. Lamprey and is applied to a component using a specifically designed detonation gun (D-gun). The component being sprayed must be prepared correctly by removing all surface oils, greases, debris and roughing up the surface in order to achieve a strongly bonded detonation spray coating. This process involves the highest velocities (≈3500 m/s shockwave that propels the coating materials) and temperatures (≈4000 °C) of coating materials compared to all other forms of thermal spraying techniques. Which means detonation spraying is able to apply low porous (below 1%) and low oxygen content (between 0.1 and 0.5%) protective coatings that protect against corrosion, abrasion and adhesion under low load.
This process allows the application of very hard and dense surface coatings which are useful as wear resistant coatings. For this reason, detonation spraying is commonly used for protective coatings in aircraft engines, plug and ring gauges, cutting edges (skiving knives), tubular drills, rotor and stator blades, guide rails or any other metallic material that is subject to high wear and tear. Commonly the materials that are sprayed onto components during detonation spraying are powders of metals, metal alloys and cermets; as well as their oxides (aluminum, copper, iron, etc.).
Detonation spraying is an industrial process that can be dangerous if not performed correctly and in a safe environment. As such there are many safety precautions that must be adhered to when using this thermal spraying technique.