Plasma spraying: the process and its applications

If you need surface coatings that are stronger and denser, plasma spraying is the smart choice. The process is relatively complex when compared to other forms of thermal spraying but the results are worth it. That’s what makes plasma spraying such a widely used process in a number of modern applications.

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What is plasma spraying?

Plasma spraying is the application of molten material onto a substrate surface. This heated material is sprayed onto a substrate where it rapidly cools and forms a coating. The plasma jet itself melts, accelerates and then sprays the particles creating surface treatments that are tailor-made to a particular application.

How the process works

The plasma gun used for spraying comprises a water-cooled tungsten cathode and copper anode. The anode takes the shape of a constricting nozzle through which the plasma gas – composed of helium, nitrogen, hydrogen and argon – passes and exits as a neutral plasma flame that carries no electrical current.

Powder like the surface treatments available from is then fed into the flame and rapidly heated. The subsequent acceleration creates improved spray distances and allows bespoke coatings to be created because the plasma stream can be influenced in terms of melting and acceleration properties. In fact, the high heat of the thermal plasma is capable of melting just about any suitable material.

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Applications for plasma spraying

Because of its versatility, plasma spraying is suitable for a wide range of applications. Plasma coatings can be composed of pure metals, ceramics, carbides, alloys and abradables and used in a diverse range of industries including aerospace, household appliances and biomedical.

Applications include biocompatible coatings for dental implants, zirconia-based thermal barrier coatings, and specialised coatings for piston rings.

The advantages of plasma spraying

Although the equipment can be expensive, plasma spraying has a wide range of benefits including thermal insulation and electrical conductivity plus advanced protection against wear and corrosion.

Other advantages to plasma spraying include:

– Wide range of substrates that can be coated making it easy to select the correct powder coating.
– Huge range of available treatments and coatings.
– Range of powder particle sizes between 5-100µm to suit almost any application.