DIN - DVS 2321
Thermal spraying with suspensions
|Publication Date:||1 March 2015|
|ICS Code (Surface treatment):||25.220.20|
This technical bulletin contains information about the current use of suspensions as spray materials in thermal spraying.
Particularly important specifi c advantages include the production of near-contour coatings in the range of 10-50 μm, as well as low surface roughness values. For some materials, such as Al2O3 and TiO2, it has been possible to demonstrate coating properties that are not possible with conventional processes. Coating thicknesses, morphologies and properties can be varied over a very wide range. With thermal insulation coatings, coating roughness depends on the formation of the columnar structures.
A particular advantage lies in the direct use of fi nely dispersed oxide ceramic powders, as these are available for the production of sintered technical ceramics with widely varying properties (grain size, purity, etc.).
The technical bulletin provides suggestions and recommendations for selecting coating materials, the characteristics of corresponding corresponding suspensions, coating production, particularly with atmospheric plasma spraying (APS) and high-velocity oxy-fuel fl ame spraying (HVOF), and the characterisation of coatings. Examples are given of coatings produced with suspensions as fi ller material.
The use of suspensions as a liquid spray material is distinguished from the use of solutions, which is likewise the subject of current research. Whereas in suspensions, fi nely dispersed particles are contained in the solvent, in the case of solutions the spray material dissociates into ions. The use of nitrates and alkoxides is examined by way of example.