Coating processes for ceramic coatings such as APS are often limited to oxide ceramics. The coatings produced are usually porous, which impairs their protection against corrosive species. In the case of precursor-derived ceramic protective coatings, fillers are added in order to achieve higher coating thicknesses. However, this always means a certain
degree of inhomogeneity and porosity.
Various preceramic precursors, both oxidic and non-oxidic, can be purchased commercially, but can also be chemically modified or synthesized. These can be applied to the substrate as a liquid coating, for example by spin coating, dip coating or spray coating. This is followed by rapid thermal treatment. This transforms the film into a ceramic whose properties can be adjusted via the choice of precursor and thermal treatment. This process is repeated until the desired thickness is achieved.