Introduction to High Velocity Suspension Flame Spraying (HVSFS)

High Velocity Suspension Flame Spraying (HVSFS) has been developed to thermally spray suspensions containing micron, sub micron and nanoparticles with hypersonic speed. For this purpose, the suspension is introduced directly into the combustion chamber of a modified HVOF torch. The aim in mind is to achieve dense coatings with a refined microstructure. Especially from nanostructured coatings superior physical properties are expected for many potential applications. Direct spraying of suspensions offers flexibility in combining and processing different materials. It is a cost saving process and allows the allocation of entirely new application fields. The paper gives an overview of the HVSFS spray method and will present some actual results that have been achieved by spraying the nanooxide ceramic materials Al₂O₃, TiO₂, 3YSZ and Cr₂O₃.