ATMOSPHERIC INDUCTION PLASMA SPRAYING

The radio frequency (RF) inductively plasma (ICP) torch is used at atmospheric pressure to melt and accelerate powder particles for plasma spraying processes. The slow plasma flow at this operating condition leads to long dwell times of the powder particles within the plasma. The powder size of feedstock cans 100 mm and more. Ceramic coatings such as alumina and titania are sprayed. The morphology of single particles, the particle deformation after their impact onto the substrate, and contact zones are studied. The deformation, cooling down and therefore, the microstructure of the coatings are different to other thermal spray coatings due to the varied spray conditions. Measurements by XRD, hardness HV and porosity are done in comparison to DC spray coatings.