The plasma spraying process uses a DC electric arc to generate a stream of high temperature ionised plasma gas, which acts as the spraying heat source. Plasma spraying produces a high quality coating by a combination of a high temperature, high energy heat source, a relatively inert spraying medium and high particle velocities, typically 200–300 m.sec-1.
Plasma Spray is used to produce ultra hard coatings of Chrome Oxide, Aluminium Oxide and Tungsten Carbides.
Sometimes technological progress and manufacturing efficiency may be constrained solely by surface requirements. For example, the fuel efficiency and power output of gas turbines or diesel engines are limited by the ability of key components to withstand high temperatures. However, it is often impractical, inefficient or uneconomical to manufacture components from a bulk material simply for its surface properties - far better to use a cheaper, more easily formed underlying material and coat it with a suitable high performance film. The resulting product performs better than the original and may be cheaper..