Thermal spray coating has been widely used for years in the automotive, aerospace, photochemical, power generation and offshore industries. However, recent advances mean that it is also now used in electronic, biomedical, and dielectric applications. Here we examine if there are thickness limitations to this technique.
What is thermal spray coating?
According to research published in the International Journal of Current Trends in Engineering & Research, thermal spray is mainly used to protect and reclaim components. It essentially applies a wear and corrosion-resistant coating to vulnerable parts.
Thermal plasma spray such as the ceramic, cermet, and metallic plasma coatings detailed at https://www.poeton.co.uk/advanced-treatments/apticote-800-thermal-plasma-spray/ have a number of potential applications. These include wear-resistant crankshafts, controlled bedding-in on turbine blades, and wear resistance on brake discs.
Coating thickness of thermal spray coatings
When it comes to protective coatings, people often assume that thicker is better but the true situation is a lot more complicated than that. There are actually thickness limits for spray coatings. This is because spray coatings are applied in splats, propelled by a gas. The splats build up on the surface that is being coated thanks to the internal stresses built up between particles. These internal stresses can only be built up so much and eventually a limit is reached.
What decides the thickness limit of thermal spray coatings?
The thickness limit of any thermal spray coating is ultimately determined by the coating material. In most cases, the harder the coating material, the less thickness can be applied. On the whole, metal alloys are more ductile, and these can be applied to a greater thickness. In contrast, ceramics are brittle if they are applied too thickly. Coatings of tungsten carbide contain both metallic alloys and ceramics, and these can be applied to a moderate thickness.
The thermal spray process itself is also important. Those using high velocity air fuel can build coatings up to a greater thickness. However, it is important to bear in mind that coatings do not need to be applied very thickly to provide optimum wear and corrosion resistance.
