Solution and suspension plasma spraying of nanostructure coatings

Pierre Fauchais (1) , Armelle Vardelle (1)

1 Axe 2 : procédés de traitements de surface

The main motivation for coating industrial parts with a different material lies on the following needs: (1) to improve functional performance, (2) to improve the component life by reducing wear due to abrasion, erosion and/or corrosion, (3) to extend the component life by rebuilding the worn part to its original dimensions, and (4) to improve the functionality of a low-cost material by coating it with a high performance but more expensive coating. Coating technologies can be roughly divided into thin- and thick- film technologies. Thin films, with thickness of less than 20 μm can be produced by dry coating processes like Chemical Vapor Deposition (CVD) or Physical Vapor Deposition (PVD); they offer excellent enhancement of surface properties and are for example used in optical and electronic device and cutting tools, Davis J.R. (2004). However, most of these thin-film technologies require a reduced pressure environment and, therefore, are more expensive with a limit on the size and shape of the substrate. Thick films have a thickness over 20 μm and can be several millimeters thick. They are required when the functional performance depends on the layer thickness, e.g. in thermal barrier coatings, when high erosion and corrosion conditions result in wear and the component life depends on the layer thickness, or when the original dimensions of worn parts have to be restored. Thick film deposition methods include chemical/electro-chemical plating, brazing, weld overlays, and thermal spray. Thermal spray processes, Davis J.R. (2004), are well-established surface treatments aiming at forming a coating by stacking of lamellae resulting from impact, flattening and solidification of impinging molten particles. "Thermal spraying comprises a group of coating processes in which finely divided metallic or non-metallic materials are deposited in a molten or semi-molten condition to form a coating. The coating material may be in the form of powder, ceramic rod, wire or molten materials, Hermanek, F.J. (2001)."

Pierre Fauchais, Armelle Vardelle. Solution and suspension plasma spraying of nanostructure coatings. H.S. JAZI. Advanced Plasma Spray Applications, InTech, pp.149-188, 2012, 978-953-51-0349-3. ⟨hal-00684970⟩