Electron microscopic studies of plasma-sprayed coatings

The ceramic coatings exhibited similar morphological features to the metal coatings in the form of flattened particles, dendritic artefacts on the particle surface, a columnar crystal structure and porosity of various forms. The columnar structure that was observed in some flattened particles may be explained by assuming efficient heat extraction through the underlying structure (substrate or coating). In a similar manner the dendritic artefacts would be expected to preferentially nucleate on the surfaces of large particles